Justice and Rule
Legend
My feeling is that 4e, PF2e, 13a, and 5e just occupy certain spaces within the range of reasonable D&D-esque, d20-derived, systems, but within that space they're not especially close. So, 4e is over to one edge on "shared class structure" and the other 3 are over in the 'not shared' category, with some variation, for instance. BA is an odd concept that only 5e, of any D&D-like that I know of, has really ever tried. I'm not particularly enamored of the results. The skill system that came out of it is rather bad in some ways, for instance. The problem fundamentally is, if you are going to have a certain range of power levels within the game, you need a certain degree of progression, and the VERY VERY simplest way, which actually seems to work fine in the other 3 games, to do that is a monotonically increasing attack and defense bonus.
They're all trying for very different things. 13A is one I want to try but is definitely the most different, seeming to move away from the class skeleton while keeping with how powers are built. PF2 feels like "What if 4E was closer to 3E in concept", where it's got a lot of design aspirations from 4E but is still trying to keep the idea of 3E. And 4E... well, 4E kind of broke the ground for the mainstream on that, didn't it? Not that others didn't do such things, but rather the biggest game out there doing it was a big deal. Really sad there isn't a proper 4.5E out there.
I mean, I get the theory, a whole bunch of orcs can threaten a 10th level fighter! Yeah, in theory... But have you ever tried to run 50 orcs? I mean, it gets old quickly and they can only actually threaten the fighter if they can all focus attacks on him, which is unlikely to transpire in any decently designed scenario. Within the limits where such things are likely to be actually reasonable, 4e manages to handle it anyway, you can have level 1 goblins jumping a level 5 party. It will be fairly predictably a lopsided fight, but I actually did it, with goblins! It worked. Heck, amusingly the goblins dice got hot and the PCs discovered that their steamroller had sprung a bit of a leak... Pitted a Carrion Crawler (level 7 standard Soldier) against a level 1 party and that worked too! So I never was sold on it that much.
It's interesting to see how certain systems deal with and others don't. Minions in 4E are a great example of solving things without having to really mess with the math: You don't need to raise someone's damage output so much that it can one-shot an Ogre no problem. Instead, at a certain level you can just do it. It's a good solution.
PF2 attacks it from the other angle: your damage does go up, as well as your ability to hit and cause criticals. Thus you end up demolishing lower-level enemies while not having to change their stats or something because the math is designed to let you do it. And if you want to do hordes of little enemies, they basically have large blobs of them that act and strike together called "Troops" that represent entire units of enemies that shrink as you whittle their HP. At a certain point your fighter isn't attacking individual skeletons, but demolishing a skeleton troop where his damage output represents him swiping away 3-4 skeletons every time he hits.
I actually like BA and dislike 5E skill system which I don’t blame on BA.
I like BA because it makes sense of why a world has level 1 up to level 20 beings seemingly living side by side. PF2 you can send a bill on orca at a level 10 PC and they won’t break a sweat. Both solve math problems of the past in different ways. So largely it’s a matter of how you want the power fantasy and/or setting sim.
Slight exaggeration, but yeah, that's kind of the idea. I do think that halving PF2's level bonus would probably be a good middle ground for both systems, but I have never attempted to math it out.