Observation: shielding is not as good in this game.
The more I play Pikachu in this game, the more I realize just how useless shield is for this character, and probably for several characters. Pikachu has always been notable for mobility (and poor grab range), but shield was still strong on him, and it's only after some discussion with others and some reflection that I've figured out why it's so much weaker as an option in this game. In Brawl, dash -> shield -> dash -> shield was a top-level strategy that worked for most characters. But dash -> shield has been weakened.
1) Rolls are stronger, and if you're shielding you can't punish rolls. Drop shield, turn around, reshield/grab/jab is harder in this game, partly because...
2) On whiff (as in, if nothing hits your shield, as Shaya pointed out earlier in this thread), shielding has 4-6 extra frames. This is huge and makes a dashing shield a serious commitment.
3) Offensive options are better, such as dash attacks and jabs across the board, so the opportunity cost of shielding is much higher. Part of this is that...
4) Grabs are worse, because grab armor doesn't exist, so you can't just grab through someone's attack. Attacking is now better than it was in the past, because it flat out beats most grabs (except pivot grabs of course).
The only time I ever shield now at least as Pikachu is vs. projectiles, an obvious ledge getup (and still there are better options), and on a platform sometimes.
I still do shield as my other characters, but I wonder if that's a mistake too and if there's a superior playstyle I could be using for them. It might have to do with the fact that my other characters are taller and less mobile overall.