The heavier characters was just something I noticed. Maybe It works for the rest of the audience I just personally thought it felt out of place and made fighting awkward, it might just be me.
It may feel out of place to some (including myself, Young Link does feels awkward when you play him for the first time. Not Fox though, Fox feels really good to me), but it does have a valid reason, character-wise, story-wise and playstyle-wise if you look into it. Also the fact that it was always planned to be that way from the start and that it stayed that way in Brawl implies that it wasn't a mistake because it was rushed, that's just the way Sakurai thinks the character should be.
Anyways I do believe the Brawl and 64 physics where momentum doesn't exist and jumping or air dodging just erases all momentum all together is extremely awkward (so is Melee air dodge, where you can just create your momentum in any desired direction, what?), it gets worse when you have a basic grasp of real physics momentum and parabolic arcs, it just feels so awkward. Yet in every game, the physics were planned that way and after playing a while you get used to it and then it even becomes second nature.
Quite honestly I have never had a gripe with any of the three games' physics except maybe for how floaty Brawl is, apart from that I think they are all really good and fun.