Deal breakers:
If I can’t make a character using a mix of Eberron, Tasha’s, Xanathar’s, and the new PHB, I’m out.
Diverse art, inclusive lore, and diverse design team.
Still feels like D&D , and specifically like 5e that we have been playing for 8 years.
I’m not really worried either of those will disappoint me.
Less important but still really important:
Fixes for the problem classes that don’t rewrite them or take from them what makes them thematically cool.
The monk has to stay a mystic warrior, the ranger has to stay more than a survivalist.
Better downtime, crafting, interaction, and exploration (mostly resolution of distinct exploration challenges, idc about travel that much.
More optional rules in the core books to lean in different directions, updating the DMG especially based on what they’ve learned over a decade.