Hi there,
what about new mobile game from you? 
You have one of the biggest base of ppl, which playing WoW, mobile devices is strong enough to handle it. I know about Diablo immo…, i think this game would be awesome, but that types of games are thousand here, you, especially you, can be unique and create only dungeons/raid:
WoW-dungeons & raids
So, from beginning, I am Michal Trnka, working as a financial adviser in a bank, and in a free time, playing ICE hockey, looking for movies with my wife, writing stories. When I have time in lunch, etc. Playing some mobile games. When I was in a young age, I was playing world of Warcraft a lot, about 6 years. Its amazing game spending with friends, when we going and beating dungeon and raids together (my favorite boss was Algaon, Raid Ulduar, event TBC raids like Black temple was amazing etc.). Now, because of lack of time (I have wife, family), I usually, same as a most of others in our age (I am 29 old), playing only mobile games little bit. I think you seeing it too, because you simplism World of Warcraft and daily activity too. Our generation it just simply doesn’t have time like usually Playing x Hours in day to have what was needed. Younger generation looking most likely on mobile games, because its more flexible. You know IT too, because you creating Diablo Immortal. Diablo will be amazing game which will succeed, I am sure of it (because it’s from you), I will be waiting to play too, but this type of games is thousand on mobile in that principle. I will show you what type of game exactly missing on market, have idea how to monetize it and how to be the best world of Warcraft game on mobile.
Princip: games like others on market are same in style. Basic is, that all ppl are dmg/dps dealers and only avoid encounter in dungeon. Will need to be improving your character, which will be usually on auto. There you Will try to get some money from that Path of improving and better loot in dungeon, to let focus on global factor anyway, which you need to get manually. Its nice principle in these games, but I it’s still missing point. A lot of people are getting lost of processing improving your character. Yes, I know, that you try to get ppl bond with their character with improving, but if its will be on auto, they will not have it. So, in that recent event, auto Battle killing games.
That game, which you should create and I giving you info in it, is different. It’s using principle from wow- tank, heal, dps, which Is amazing. There are games like that, sure, and two are good copies of wow, named world of Kings (more than 1 mil download), and better Era of Legends (more than 1 mil download). Why you think that games are success and have that number of downloaded is simple, because it’s like wow. I find that games, because I wrote: „games on mobile like World of Warcraft". Its show this. So, I try them, playing little bit and showing you, what Is good in them and what is bad.
What is amazing: dung and raids/pvp- amazing experience like in wow, you playing what style you prefer, communicate with ppl, enjoyable time. This thing giving you plus and the most people playing it because of this. Yes, developers usually doing their end encounters to that style, which Is fine.
What Is bad in these games and getting rate low: It’s not interesting for me, because basically everyone says: "auto fight, too much management and Focusing for monetize thousand If events. If I write little bit more of it: improving in these games on auto Is boring. It’s getting you like looking on video, which Is annoying. Basically, you say, you must survive it to get to better game, Meaning raids, higher level etc. They hoping that in processing it, you will spend more money, but they don’t se see how many ppl losing because of it. On store in all bad stars (review, rate us, etc.), they get 1-2 with usually comment "auto Battle.
Second Is: Owners here want to want to much with management and events, that you even can’t do anything else, you just need to do that events and actually loosing connection between your character if you see that there is like 25 events (on maps, It’s like roulette of events) which you need to do and 15 different ways to upgrade your hero. Even if it’s Simple, Its annoying.
So, in that principle, be best where you can be, what ppl want and, because you can do it, don’t create which ppl don’t like (go again everyone, show them how it can be and profit from it)
Create game only for dungeon, raid and pvp with daily activity (idea bottom). Don’t do there any exp and auto mode on this game, it Will again destroy game, be different. You have the one of the biggest basements of people, which looking for that game, where you can raid, dungeon/pvp talk with friends and spending there less time, because they don’t have time on World of Warcraft on Pc. There aren’t any game of these, you will feel the hole and get profit on it. mobile engine is right now strong enough to survive with easy dungeon, raids, on mobile.
So how you can do it?
First of all, use principle tank, heal, dps, buff, debuff - wow etc. (Will wrote detailed later)
Use like all of your class (war, Hunter, …), everyone can create every class, because they will be needed. All classes will work on one second casting hit/heal/cd, instead of instant. Instant cast will be there special ability.
All of classes Will have 4-5 buttons: 2-3 on will be on attack/heal - one major, which will have one second cast. One dps/ heal, which should have about 10 second cd and doing double dps/heal and one aoe dps/ heal, same 10 second cd, doing 1,5x aoe dmg/heal. One will be on buff/debuff (explain later), and last one will be for survive (survive will have about one-minute cd will remove all dmg and having you invincible for like 3 second).
Use crafting needed for class automatically, nothing special, which will need materials from dungeon/raid/pvp, to creating gear (you can choose, if there will be overall 10 types of gear or more -helmet, gloves, rings, weapon, …), nothing more (they will be creating what gear can want, if they have rrs on it) and one second profession (fishing, cooking etc., which they can choose, where they can create money and boost Stats little bit).
Gear: from Common to legendary, every Stats on it will increase like about 5%. (So Common gloves from dungeon get 5%, uncommon 10%, rare 15%. From raids its start like common is about 5% stronger than dungeon, more bottom)
Game will have simple and amazing with all together. All where they will get progress will be from dungeon/raid10/raid 25/pvp. Dungeon will have 5-10 levels where you will get drop dust (higher level, higher dust, higher gear), which you will need to creating your better gear. There will be 5 levels of gear se you know (Common, uncommon, etc.) Drop from raid will be one step higher than from dungeon (like dungeon uncommon set will be like raid 10 Common set, raid 25 Common Will be like rare dungeon.
Daily activity will be simple too- like only 4 activity, doing pvp, dungeon, training (because challenge Is hard, explain later, you will try survive one min on training) and activity (fishing, cooking, first aid). They will get gold from it which again, will need for creating gear.
So, this Is Basic principle, now how it will work.
All about will be in dungeon/raids/, which as you will be surprise, will be simple, but hard, to get and be here for progressing (we ppl from wow like challenge, game itself cannot be simple, there are thousands of these here, game must be challenge like progressing boss in Wotlk, Tbc, etc.) Basic will be, that there isn’t be trash (it was wasting time, it’s pointless here to try delaying content), it can be only boss, one boss, which you need kill. Usually fight will be about 7 mins (10 mins enrage), you will have to cooperate and looking, how boss work. Itwill be debuff/buff style and you will combine, what Is best for you. Ideal Is, that you will need even change class for doing it.
I will start about boss: in 5 ppl dungeon, there will be one boss, in 10 dungeon 2 same bosses, in 25 3 same bosses, which will have random debuff and random spells. From beginning they will have buff on self, that you need use specific class to have him weaker (like buff on himself, which will get Down only with using Hunter debuff - all class will have unique debuff to be using only him, same as can be tank only with that type of hero, otherwise he will be unbeatable). Every boss will have 25 random skills, which is setup on every entry to dungeon/raid (ONLY in entry, not in wipe, they will progress and teaching how boss work)
They will be settings little bit differently on which encounter (dungeon, raid) And how difficult dungeon/raid it will be.). Boss will simply hit for 25% tank hit point every second, they will kill him on 4 hits, 4 second, healers will have power heal 30% each cast, each second, can cast simply heal it. Boss will cast every 10-30 second some random ability (higher hit, ability which you need to dodge, …). His Stats will work simply, on first level, they will have no buff. But on second level, he will have +50% stats as it should Have ppl, because they should have same (all Common gear give 5%, it could be here 10 items, Meaning 10x5% =50%.) If not, that your boss can kill tank Faster and will have more Stats, Meaning that dps need to kill him to 10 mins or it will enrage, instantly kill everyone… this is principle of all stats, like you can kill higher level, but best way is to have same gear stats as boss and its same like you challenging same encounter as before (but he can have higher and difficult abilities…). In 10 raids, his stats will be +50% even on beginning, so you at least should have cleared all first dungeon to have +50% Stats too. On 25 raids, there will be +100% Stats, so you need to clearing 2lvl of 5-man dungeon or 1lvl to 10 raid dungeons, to get that gear which you can handle.
If you see stats principle, there its simple, it doesn’t be there some higher calculation, you will just set start point and everything will get + Stats to it.
I have in paper like ability which bosses can have, how encounters should look etc.
And what is most importantly, how you monetize it?
All daily entrance will be limited like to 5. You can do 5 dungeon/RAID/pvp to get basically 5 pieces of gear if you are lucky. More in day you can’t do if you don’t buy extra tickets entrance for some cash. That means like in a 1-2 hours of day, ppl can do all works in daily. Its active playing, nothing auto, so its maybe too much for someone, but they can spend there like and half of hour to speak with friends, do some encounters etc. Basic is, that you will get a long term of fun, still progressing and still what to do. Ppl will play it because there will still see what Is behind them and want to achieve and kill last boss (and you can create more of it)
Same it will be will gold, which you need to upgrade your gear. You can earn by secondary profession or you can buy them.
Next you can do there as in wow, monthly payment, which gives you some daily money and like more entrance (like plus one).
I have ideas how can be setting with class (maybe it can be fixed like on your account and you will progress whatever your character will need to play, because you will need changing it), how boss ability should work, and much more if you like and are interesting in that :).
So, write me pls what you think about that, if its Meaning something :). Thanks