Very important system changes:
- Reactions
- Ritual casting
- Ready an action
- "Special"-Actions done right (things like sneak attack, smite and some BM maneuvers)

Nice improvements:
- Improve the push action (let me choose push prone not push away)
- Grappling
- a better combat log (at least as an option): i think its annoying to have to hover over spell names and attacks to see my dice throws

Personal wish list:
- Xanathar and Tasha content being affirmed and some things also maybe included (like tashas custom lineages)
- Aasimar
- Hexblade, Forge Cleric


What I don't want: more story. I wanna test the EA to help make the game better, but I still wanna enjoy the full release without having played half the story already.

I also get that people want to play new classes, but I dont understand the worries that classes would be hard to implement. Some modders already done great work with that with limited ressources. As long as the 5e *systems* are implemented right I have no worries about classes down the line.