Personal anecdotes
Don Vu got top 100 on Wizard, Crusader and Mon on the Solo GR Leaderboards in S1
Wyatt Cheng had a Monk and Wiz in HC, a DH and a Crusader in SC
Travis Day got up on the solo and 4 player Leaderboards pretty early in the Season
Wyatt Cheng died because his hotel internet died on him and was texted his death message by Travis
Don and Wyatt tried the Speed Racer conquest, even using spread sheets and recordings of their runs but only managed to get it down to 1 hour and 3 minutes
Seasons
Seasons should bring a sense of community, like watching your favorite streamer push Greater Rifts on a new character
Season 2 will focus less on levelling speed, because of the "clever use of game mechanics" we've seen in the past
The Pylon, GR layout, and density changes should help Season 2 and make GR success feel left dependent on RNG
Future Seasons should be shorter than 5 months
The patch cycle will have an impact on Season length. New content patches will likely only happen in the breaks between Seasons
Conquests should help diversify the gameplay experience and offer something for all types of players
Wyatt worries that there might be too much focus on Greater Rifts and less on simply enjoying your own progress, so the game should acknowledge your accomplishments more
The best GR group composition does change over the duration of a Season since balance is in flux
Making the Legendary Gems Season-exclusive was done to make Seasons more appealing
The team is pretty happy with how much use the Season 1 exclusive items have seen so far
Gameplay changes for future Seasons are still being discussed. What if you couldn't heal at all? Such Seasons would be much shorter, though.
Other
A hotfix for the "Talk to Alaric" quest (which was used to powerlevel) is being worked on
The Ancient Items idea started when Travis had all the gear he wanted 2 weeks into the season, so they wanted to create something else players with the best Legendaries could still strive for
There used to be a tiered Ancient items system but it didn't provide for much additional benefits while having too much unnecessary complexity
Diablo should be a game that you play until you reach a certain personal goal, then put it aside for a while and come back to later, for example for the next Season
The new sets we were shown at Blizzcon are still being tweaked but the main theme should stay the same
Autopickup for crafting materials and gems would disconnect people from what they're getting and maybe not even noticing that they picked them up, though they agree that it is annyoing to pick them up individually
The Ring that rotates between elemental bonuses (the idea from the Blizzcon Workshop) is already usable in the internal build
The Tal'Rasha set will get new pieces and a 6-piece bonus to become viable in a future patch. The same applies for all other classic Diablo class sets
Legendary items and Sets are what will provide build diversity in the future as they are being expanded upon
The Sunwuko set was changed because spamming a Mantra to deal damage felt bad and the repetitiveness could become physically painful
Adventure Mode/Bounties burn people out later in the Season because farming a RoRG becomes too repetitive, which is something that's being looked into
The team is happy with the performance of 2-handed weapons vs. dualwield, they don't need to be perfectly balanced
The goal is to put Legendary powers on all items, Mighty Weapons have not seen a lot of love until now because items which everyone can use were deemed more important
There's no Fire Legendary Gem because fire is already the element with the most support from other items
Instead of reworking skills, the team wants to focus on making them viable via new Legendary items
The Nemesis system will likely not be coming to PC in the near future
GR Trials are still being looked into, one reason they're really useful is finding the right GR tier in public games
Succubus debuffs have been reworked in an internal build
Builds using legacy items are fine, the only problem is that some players have no way of accessing their play style. Maybe new items which allow for the same play style will be added to make them accessible
The Blood Shard cap is in place to make new players figure out how to use them as well as for experienced players to not defer the reward from it for an unlimited amount of time. The issue is brought up every week in the meetings and thus frequently discussed. There might be a way to increase the cap in the future but no details yet
Using Rend as a WW Barb should feel like a moment of weakness, that's intended as it should change up gameplay a bit
No higher difficulties are planned right now as that might make regular Rifts and GR rather similar, but it's not out of the question
Forgotten Souls being sparse for fresh characters and abundant for well geared characters is something that's being looked into
Lack of diversity in rings is something that's acknowledged and rings that are as strong as Unity/SoJ/RoRG are being worked on
Focus and Restraint will be improved, but not in the near future
The traditional trade system was talked about a lot internally but the negative side effects (item selling sites, shortcircuiting the reward loop) seemed to outweigh the benefits
Clan trading would make you see your clan mates as utility, as a way to get items, instead of people to play with which is what clans should be about
Kadala will probably not give you the option to specifically gamble for weapon types because you should be getting other items on the way which might not be what you want but still something you'd give a try
Upcoming Sets and Legendaries might make single-target skills more viable, e.g. the Monk's Dashing Strike set was reworked to do this (it's now very different from what was showed at Blizzcon)
Activities on a clan basis are an option for the future but clans should remain optional and such activities are currently low priority
The Helltooth Set is still being worked on
No DPS meter
No plans for more 2-piece sets
Having support roles in GR groups is fine as long as they're still fun and challenging to play