What do you wish D&D 2024 would have done that evidence says it isn't?
Make all subclasses begin at the same level, and pay a thought to mixing classes and subclasses, so that a Rogue or Ranger can take the Champion subclass, for instance.
(It's fine if this compatibility work only extends to Martial, Arcane and Divine classes. For instance, if it's a bit wonky if a Sorcerer or Druid takes Champion, because that's crossing the Martial/Arcane/Divine divide, that's okay.)
Okay so now all subclasses start at, say, level 3. Then make them end at mid-level (and again, all at the same level). Say level 11. This opens up an important decision upon reaching level 12 that impacts high-level play, which will put much needed emphasis on high-level play. (Your second subclass would take you from level 12 through level 20, meaning that instead of making a single decision at low level that you have to live with "forever", you get to make one decision for low to mid levels, and another for mid to high levels. Both subclasses would now also be of equal length; nine levels).
Every spell that the various guides out there rates red should be significantly improved, or redone entirely. (Yes I know there is value of having subpar spells you can give to high level caster monsters, but a spell every guide agrees is red is simply a waste of PHB space)
Every spell (including Fireball!) that's rated sky blue or gold should be nerfed slightly. WIth many more spell options roughly comparable, we will see more varied builds, approaches and strategies. This is a good thing.
I personally don't like the way Summon spells are fixed. I would have loved an approach that still lets players pick critters from the Monster Manual, with all the variety that entails. Summon spells with genericized stat blocks is a pale shadow to that.
Regarding feats I believe the official info already suggests fairly significant fixes, so nothing to say there.
Lastly, reinstate the goal of pricing magic items using a utility-based rational approach. No more picking price numbers out of thin air, or make prices relate to rarity - rarity has no connection to how useful an item is to help an adventurer survive adventures.
Edit: If you wish to discuss these specific ideas, here's a thread:
For a while now I've been frustrated by the lack of a product that enhancens and deepens 5E without shooting off and making a new game. There's been quite a number of supposedly saviors of 5E that upon inspection (or right away) turns out to be something else than 5E. They change up the classes...
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