Hey, I have recently finished Playthrough on Hardcore on PTR patch 2.4 as pure Summon druid. As someone who never played summon druid I would like to share what I have find out and how do I feel about new changed summoning skills. I of course know that summoner sucked before changes, thats why I never played him 
NORMAL DIFFICULTY
NORMAL DIFFICULTY
Normal is honestly piece of cake, Ravens all the way to 20 with only 1 points into poison creeper, Oak Sage, Spirit Wolf, Carrion Vine and Dire wolf.
Remember Maggot Lair and Arcane Sanctuary with summond necro? So bad right? Well not with Ravens, they dont care and kill everything easy and even in pretty far away from you. Hell you can even do the “moat trick” on mephisto with them lol. In maggot lair you can spawn ravens close to enemies to help them and they will kill them easily. Later on higher difficulties I was also using Grizzly casted in the backline.
Maybe you are still scratting your head about something. Why the hell I use Carrion vine?
Well because now its actualy great and is constantly healing you in fights+destroying bodies of enemies with stronger effect sooner. But maybe druid pros were using this skills frequently before and I am just noob who didnt know. I didnt play PvM druid before really that much.
Anyway, when Ravens were maxed, i continued with Spirit wolves until I could invest in Grizzly and then I fully maxed him. He is amazing tank, practicaly never dying. When I was fighting Diablo, my summons were destroed but not my:
Indestructible, cannot be frozen, poison, chilled, cursed, targeted Ravens
I was jusing jogging around Diablo and waiting for them to kill him, it was just matter of time. ACT 5 was also easy. And after I made level 40 I tried few secret cow runs and to my suprise, my summons were destroying cows even on players 3 quite well. Or maybe my merc played big part in it. I was using frenzy act 5 merc with Steel runeword in gladius and he wrecked enemies.
NIGHTMARE DIFFICULTY
NIGHTMARE DIFFICULTY
I am quite experienced Hardcore player so I invested total only 5 skill points in Oak sage, because I was willing to lose some health to max out my damage from summons first. I ended the game with those 5 points in Oak sage. Its Basicly like if you would have Call to arms on your char, life is not super high but decent to survive if you dont do dumb mistakes.
I was quite suprised how well were summons+merc doing on nightmare. I was little bit afraid, but they were demolishing everything, and then I realized I was on /players 3 lol.
I was aware of issue with immune monsters so I hired ACT 3 fire mercenary who kept enchanting my weaker summons with some fire damage and also he was doing quite good damage to physical immunes with fireball.
I eventualy made it to end of ACT 5 and everything was honestly still fine. Only minions of destruction were harded to kill and I had to use little trick with ravens so they focus all only one of them as distributing summons to various targets was not good as they could not kill them. The trick is described under skill review.
HELL DIFFICULTY
HELL DIFFICULTY
I knew troubles will come on hell and I was partialy right. Progress slowed quite significantly but I dont think it was that bad. I was extremely unlucky with Druid pelts and was using Lore helm whole game.
The issue is that majority of monsters on Hell have physical resistance and some monsters even 50% or slightly more. Unlike necromancer who can use amplify damage to increase dmg output by summons multiple times, Druid has nothing. Well they changed Spirit wolves so they do Cold damage now, but its honestly useless. Even at high levels is cold damage they do too weak to do significant difference.
My spirit wolves were basicly just meat shield doing low damage because of low cold and fire damage (from enchant). The reason why they dont do that much damage is because many monster on hell is resistant or cold immune. What is the worst is that most physical immune monsters is also highly resistant to cold and ghosts are very often both cold and physical immune.For that reason was ACT 3 fire merc essential to deal with them.
I still think I managed to finish hell in reasonable time (8 hours 20 minutes) when we consider that I was untwinked characer who didnt do any MF runs outside of my playthrough if I dont count like 2-3 normal cow runs and few NM baalruns to level up.
Biggest problems I had were monsters with physical resistances and big health pool, for that reason was ACT IV too time consuming and boring for me as there is so many monsters like that. And my wolves started dying in chaos sanctuary quite a lot.
Ancients were fine, I would even say easy and thats rare to see. I am not aware of any other build who could deal with them so easy. Baal was struggle tho. He kept destroying my wolves very fast and dmg from my summons was just so tiny. I had to hire act 5 frenzy merc and give him that steel gladius from normal so he can do some crushing blow to baal. And then I was able to kill him.
SKILLS REVIEW
SKILLS REVIEW
- Ravens - they do a lot of damage and will carry your build even on Hell. I found out that there is little trick to force them to attack who you want. You simply put your cursor on monster and keep casting them on that monster and they will usualy focus it as its enemy who is closest. Ravens have also quite long range so they can attack monsters you dotn even see sometimes on screen.
- Poison Creeper - I didnt find any use for build i was making, but without points in spirit wolves, maybe this would be interesting option to have different damage type. It is certainyl very strong skill early but it lacks damage later on and some monster are poison immune already on normal. Or highly resistant.
- Oak Sage - Very good skill to help you and your summons to survive dangerous encounters. I had only few points in it but felt much safer when fighting souls for example. If you are skilled player, this skill doesnt need to be maxed, you will not have enough points anyway without sacrificing some damage from other summons.
- Summon Spirit wolf - I think changing damage from physical to cold was not a good choice, it damaged build more than it helps because cold damage is often resisted and not high do something. Decision should be Magic damage, that would make more sense. Spirit wolfes are more cannon fodder and meat shield than good damage dealers.
- Carrior Vine - I usualy like to use merc with prayer so Carrion vine was great skill for me, providing constant healing in fights. I am just not completely sure how exactly it does work. If % of healed damage are used based on monster corpse or your own Life. It looked like it was healing me same amount most of the time.
- Heart of Wolverine - great to increase damage of your summons, except its useless for spirit wolves after damage type change to cold and ravens also ignore it.
- Summond Dire Wolf - they deal good amount of damage fully maxed together with grizzly.
- Solar Creeper - just useless, there is no reason to use this over Carrion Vine for summoner
- Summon Grizzly - Your best summon, high damage, attacking quite fast and he can take a lot of damage before he dies. I used grizzly often to attack enemies from both sides. I let wolves attack infront of me and then i summond grizzly behind the monsters so my summons werent blocking each other in certain places like arcane sanctuary.
Something is missing right? Yes, Spirit of Barbs but that skill needs to be replaced. Its is garbage even on skill level 44. I think Spirit of barbs should be providing -% physical resistances to enemies as aura so it doesnt block curses. Lets say level 1 would lower it by 10% and then every hard point in summoning tree as synergy by another 2%
FINAL THOUGHTS
FINAL THOUGHTS
Druid summoner is honestly fun build to play, little bit slower on hell without good equip. He is extremely safe build for hardcore and you can finish the game without some extensive item farming even if you rush things a little bit. I for example rushed majority of hell.
Can summoner be good MF or rune find character? I dont think druid summoner without more expensive equip can achieve same effectivity as other characters. But that was case for druid always. Rune farming in most cases require a lot of killed monsters in short period of time and druid doesnt have corpse explosion as necromance. Druid´s summons struggle against a lot of enemies and you need to invest majority of skill points to develop them.
I have tested my build after I have done playthrough in Pit and it can be one of the locations you can farm for MF quite well, its not just super fast. It is important to gather as much MF as possible on items without +skills, because summons really benefit greatly from +skills on equip.
THEORY CRAFTING
THEORY CRAFTING
I was trying out few things to find out ways how to improve the summoner build. In my opinion it could be maybe worth ditching Spirtit wolves and invest skill points elsewere but it would require more testing how is rest summons holding up without points in spirit wolves. Ravens will certainly do less damage without points there.
I was trying hybrid build where I used points in shapeshifting instead of summon spirit wolf and was using Lacerator as main weapon+ shock wave to stun enemies. Lacerator for Amplify damage effect of course on striking. The issue is that ravens do cast blind over amplify damage on regular enemies. But its great against elite mobs and Bosses. I believe some item has also grim ward on charges, but it would be only -20% physical res to regular monsters.
Infinity on Might ACT II mercenary might be also interesting choice as it will boost physical and elemental damage of your summons at the same time against non cold immune monsters.
Sorry if some things dont make that much sence. I am writing this when I am pretty tired and its very late for me. I just wanted to have it posted before i will go to bed I could certainly write more but i didnt want it super long. Its already a lot of text.
If you want to watch some important parts of playthrough or full hell playthrought with HC druid summoner, you can watch my whole finished playthought below
You can check other videos folling that one with Duriel. I will just post last vidoe with act 5 hell also so people can check final build. I am showing all my skills and equip at the end:
