I agree with a lot of the design ideas they're making, but I have, overall, been very disappointed in their actual implementation of them.
Fixing the power imbalance of summoning and shapechanging? All for that. Actual implementation?

I can't swim until what level? I can't fly until what level? Er, have you read the spell list, friends? Is Wild Shape supposed to be a primary feature or not?
Many of the other changes, like spell schools needing to matter (and still having three spell lists!), and the class groups, just feels like chart-filling being used as a crutch for game design. It feels like what it is. They don't have an idea for the fantasy of what each class should be anymore, so they're just shuffling through different iterations of the same design, peppering them at a different levels for variety, and going nowhere fast like
Daffy Duck struggling to escape the animator.
Plus, they're pushing even more abilities even deeper into the class level structure. Part of it is more chart-filling-as-design, but even more is because multiclassing is a really, really stupid design. Stop nerfing the classes to make multiclassing less unbalanced, and just add real costs or penalties for multiclassing already! Or just drop it entirely! There's 12 classes and 48 subclasses! It's so much nonsense for that one thing to drive so much of the game's design. Give me a fleshed out character at the start of the game. Words cannot express how uninterested I remain at the idea of playing a War Cleric who doesn't know how to use a sword or armor until level 3 just because multiclass dipping is too good if you're a Sorcerer! And OneD&D is doubling down on that design. Now
nothing from your subclass will be available until level 3 for
any class. Everybody is generic until level 3 now.
It's like they've completely correctly identified the parts that are broken, but are otherwise doubling down on everything I didn't really like in 5e.