I think for D3 it’s sort of a lost cause at this point because it has no PVP and had no vision for endgame going into the project. That’s partially why (the AH going away is a big one too) I think they jumped ship part way through and switched to D4 development. What can D4 do to avoid this same fate?
Well, I think it comes down to cleverly re-using assets and delivering on multiple game modes.
Keyed dungeons is a fantastic start because they reuse existing game content and add different ways of playing those. The developers could get really clever with the keyed dungeon affixes to make them completely replayable and hopefully challenging. The best difference between these and GRs are the story they tell. If you mention you had a crazy time in Garan Hold lvl 20 dungeon, that’s a place that others in the game know and understand. GR floor 150 has no image it conjures since everything about GRs is random.
The way you replace GRs in D4 could be a really long dungeon (50-60 floors with reused campaign bosses every 5 floors, essentially Diablo 1 nostalgia here) that is semi-static in terms of the tilesets and monsters it uses (so players can share stories about where they ran into trouble) that has different game modes.
- Endless Mode - Finish the dungeon and then restart it. It gets harder the second time around. Finish it again and restart it. etc… The catch, you only get so many town portals to finish it in a single run similar to mapping in PoE. You could have endless mode leaderboards - who has descended the farthest?
- Speed Running Mode - Once players become accustomed to the initial layout of the 60 floors, you can add a speed running mode to it. The speed running mode could be spiced up by having pylons on each floor that empower the bosses on lvl 5, 10, etc… Do you kill the pylons or go straight for the boss? There could be speed clearing leaderboards.
- Rogue-like Mode - You go in with your gear and your build, but each level you clear you get to pick from new powers. The difficulty curve becomes insanely hard in this mode such that if you don’t have good enough gear initially, get a good combo of powers and/or special items that drop only in this mode, you won’t be able to finish the dungeon. All special powers/items from this rogue-like version of the dungeon disappear after you finish it and don’t carry over into the game world as normal (call them ethereal items if you like to recapture some D2 nostalgia), but there are rewards for finishing it that are unique from those you can get anywhere else in the game, so people will have a reason to run it.
- Once people get tired of this endgame dungeon, you introduce a new one in season 10 for example, that has new strategies, designs, etc… (but still could reuse a lot of game assets) and now you have leaderboards for both dungeons.
PVP plays a huge role in endgame content potentially since if you find yourself not up to the task you need to go farm better gear and/or practice the content more to get better. Incentivizing the competition here - special items that drop in Fields of Hate that can be claimed for monsters but stolen from players (in addition to the already announced shards).
Use already announced camps and sanctuary factions (like the rogue will be taking quests from) to introduce weekly faction reputation game play like you have in MMOs.
Make re-running bosses in the campaign necessary to gather crafting mats for a crafted only slot like they have in Grim Dawn. This could bring back the feel of boss farming in D2. Some of the crafts could be quite rare and include PVP itemization - the only slot that could have such affixes for those interested in PVP.
Allow players to restart the campaign (for those that like to run the campaign) but have all the non-shared world content (dungeons, boss encounters etc…) scale much higher and give endgame rewards like what you can get in keyed dungeons etc…
Support a speed run campaign mode with leaderboards.
Diablo could have awesome, story add-ons introduced in seasons. Play through this season’s story. Example stories.
- Assault on the cow-kingdom - a DnD style adventure to help the cow king recover his throne - similar in feel to the Tiny Tina assault on dragon’s keep story addon in Borderlands 2 (may be too whimsical for D4’s feel, but I’m just brainstorming).
- A crazy night with Shen - Players solve a murder mystery alongside Shen from D3. Shen points out different dungeons he remembers being in and you have to clear them to find clues that will help you piece the night together.
- A treasure hunt story - You are enlisted by one of the rogue factions to find keys at the end of several dungeons to unlock a secret vault in Caldeum. Takes a long time to recover the keys and the vault has several new guardians.
- The Return of the Countess - climb the countess’ tower to reveal her dark past (puzzle themed tower climb experience)
Personal garrisons with siege defense, or even tower defense style modes.
All of these ideas need a ton of polish to be sure, but we can do a lot better than only keyed dungeons / GRs / mapping at endgame.
The ultimate endgame though is having a ton of builds that seem diverse and interesting so you feel good about making a lot of characters.
Not all this stuff has to be in the game at launch, but to say there’s not a solution is crazy-talk to me - there is no limit to the crazy ways they could reuse game content with a modicum of investment. Out of all the game world’s genres ARPGs seem to have evolved the least over the last 20 years when they have the ability to evolve more than most other types of games. The ARPG endgame scene is criminally under developed imo. This likely has to do with monetizing ARPGs, but PoE has shown a cosmetic MTX based monetization scheme can support the game long term to allow things like this to be developed. I just hope the D4 devs are bold enough to break the mold.