This thread has been sitting dormant for seven months and some newer playtest packets have come out. Most of the packets have been about giving players new goodies, which are nice, but don't really reflect the problems of the current game. Here are some things that I still have not seen (but still have at least some hope that they might occur):
1) more dangerous and interesting monsters (at least for CR 3+). Most monsters are not scary enough to PCs once they reach 3rd level or so. I don't think monster HP should go up (don't want to make combats go longer), but I think monster damage should increase. Monsters should have more special abilities or riders that attach to their standard attacks. 5E monsters are kinda boring compared to 4E or PF2E. I was actually pretty sceptical about weapon mastery properties at first, but they could make 'NPC' monsters (like veterans, knights, bandits, noble, etc.) more interesting. Monsters should have more skills as well for the purpose of opposed roles (in particular, Athletics). Note: since the playtest seems to be increasing character abilities, monsters will need to be increased even to maintain parity.
2) fix the EL math (that's pretty much a given)
3) provide some some of penalty to PCs who recover from the dying condition. I like the 3 death save concept, but I dislike the cycle of how unconscious characters can get 1 HP of healing, pop up, get dropped again, get 1 HP of healing pop up... The game would benefit from either having failed death saves be removed on a long rest (like 4E), or something like the wounded condition from PF2 (maybe a level of exhaustion?)
4) change short rests to 5-15 minutes and limit characters to 2-3 short rests per day. Shorter short rests are obviously much more available to characters and wouldn't normally impact the game fiction in the way that 1 hour rests do. This would fix most of the game problems that WOTC is trying to solve by moving everything to X times per day AND result in less nova-ing behaviour than the current solution. Seems so obvious, I don't know why we haven't seen it yet.
5) give characters something to do with their wealth. In the current edition, there isn't anything interesting to buy with treasure (unless you want to buy plate armour or add spells to your spell book). Yes, you can buy property, but that doesn't fit many campaigns.