Here's what I want from 5.5E.
More DM materials.
More then anything, more DM materials. I want them to actually hire people who know story structure AND game design, and can combine those two things into good experiences.
This might be a hot take, but most stories released by WotC for 5th Edition are sub-par at best. They are clunky, written by different people, don't often make sense, make unclear assumptions, and often don't live up to the hype and idea WotC markets them as.
Out of the Abyss was supposed to be Wonderland in the Underdark and scary. It wasn't.
Storm King's Thunder was sold as a Shakespearian Epic. It wasn't.
Tomb of Annihilation was at least close to what it wanted, but then I got this cringe culture on Chult that was just a bunch of black people needing their foreign white saviors to help them because they are too busy going oongo boonga in the jungle or getting drunk on Capitalism. I'm black, by the way, so this isn't racist, what's racist is ToA.
I wrote a whole essay on how Avernus failed to be Mad Max, or anything close to it.
That isn't to say people don't have fun times with these adventures. I know about 5 people are going to read this and quote me saying "My group loved blah blah"
But guess what? I loved Transformers 2, and that movie is still dog water.
WotC could be making far better adventures. I can see great ideas in the OSR and 3PP realms, but all the WotC stuff constantly feels half-assed, and I really can't run it. Not just because the assumed story is usually sub-par, but because the layout of the books is just almost unnavigable. I gave up on Storm King's Thunder because with all the prep I had to do, I was basically making my own adventure and filling out EVERYTHING. EVERYTHING.
And I'm TIRED of it. I just want adventures that are both good to read AND good to play. It isn't all that hard! But they seem so dedicated to the story writing and narrative techniques of the 70s-00's, that they have failed to create anything even remotely compelling to me for this generation.
That isn't to say there isn't good lore either! Even though most people hate the 5E lore, I actually prefer it to most other D&D editions. But none of that lore matters; in fact, it matters less now then it ever has.
Just for God's sake give me one good, well-written adventure. Please. Please. Just try.
And fix the art. God, first party D&D should always set the bar. This edition, it constantly misses the mark.