With the recent playtest and the continued express commitment to backward compatibility on the 2024 rules release, by whatever name. I'm wondering if backward compatibility from One D&D back to 5E will truly work. The changes being tested seem to indicate not.
Grappling not using ability checks to grapple makes useless abilities, feats etc. that relate to those checks. (including for the Plasmoid published this past week).
Crits, you could always do the way you want but IMHO this playtest represents a less fun option, and where do I recycle my Adamantine Armor?
Backgrounds having feats. What if you already have that background but not that feat. Is your character still compatible? If backgrounds can be customized, then every background shouldn't need a feat, especially with feats having been an optional rule in 5E. what if you're the variant human with a feat that is no longer 1st level?
Why rewrite feats that players like? It raises the question, 'If I have Alert already and want to keep it, it my character still valid by the new PHB? Will legacy options be available? What about the half races? Same question. If I like my half orc character and like Relentless Endurance do I just lose it? What if my dwarf likes the existing stone-cunning? or if I want mountain Dwarves to be different from Hill Dwarves.
Does the wording on natural 20s and ones call out that some things are going to be impossible regardless of the roll. (and they should be).
I'm sure there are other things, but if backward compatibility is going to be anything other than a lie, we're going to need a lot of this very limited playtest to be revisited. i.e. Have grappling include things to do that will use an ability check, like pinning an opponent, let crit restrictions be optional or drop it. make customizable background options that don't include a feat or include an alternative benefit.
drop the level prerequisite or allow 1st level to trump the prerequisite.
drop the re-write of feats like alert or lucky and re-write ones that nobody takes, ever. I'm looking at you weaponmaster. Stop trying to fix the wrong problem and simply edit the PHB with changes that do not hurt backward compatibility. Start with options that no one uses; bad feats, useless spells, unplayable sub classes, features that players or DMs ignore now. That would boost sales of the new book(s) because fans have been hoping for those fixes in official rules for years.