Also, D&D suffers from boring level ups where you don't get to make any decisions,
So my take:
+1 ASI every two levels.
Feat every three levels. (feats can be rebalanced and with level requirements)
ok, but you are not really addressing the problem that you have mentioned. D:OS2 have you attributes every level and it was still boring, because attributes don't develop character in interesting way - they just get progressively better in a very boring and uninteractive way in the thing they are already good at.
Maybe multiclassing will spice things up a bit?
That's the whole point of feats, really. It's to spice things up and make your character more interesting. That's why I chose Both in the poll. Ultimately, I'd like to see more feats in the next edition, and I'd like characters to be able to get them without sacrificing ASI - because ASI appeals a lot to players.
For example, I created a Master of Disguise Wood Elf named Diadell. Her character when I developed her was supposed to be really good at pretending to be other people; very good at fooling people with her disguises. Having the Actor feat at level 1 would have been REALLY nice for her character build. It would have fit her very well. Then, later, at like level 3, it would have been nice for her to be able to get Quick-Fingered because she was a rogue Arcane Trickster as well who used her disguises to get close to her targets. Then, at maybe level 4, she could increase her Dex +1 to 16 to gain an extra boost to all her Dex skills, making her a more efficient rogue and master of disguise. Instead, she got none of these and the player had to choose: ASI OR just 1 of those feats. Hmmm. Which was more important? And, until level 4, the character wasn't really all that great at being a master of disguise. Sure would have helped to give her Actor right up front.
That said, in terms of BOTH, 5e kinda already has some of that, depending on the Feat you choose. Take Quick-Fingered, for example. You get an increase to Dex (+1 to the score) AND you get proficiency in Sleight of Hand (or expertise if you already have the skill) AND you can do Sleight of Hand as a bonus action to plant something on someone, conceal an object, lift a purse, or take something from a pocket.
The problem with BG3 is that we don't have a lot of those kinds of feats. We have a lot of the more boring feats that don't really seem worth it to choose Feat over ASI.
