Well, when a move whiffs, it whiffs. Especially regarding characters with swords. They're supposed to aim their attacks so that the sword strikes the opponent, not their armpits. A lot of the examples in the OP are "well duh" moves. A high angled attack will miss a low crouching opponent. As for moves whiffing at point blank, it is unfortunate but try spacing it in the future. We never complained about this in previous smash games because it was moreso the player's err than a truly faulty hitbox. Furthermore, most attacks are not designed with the possibility of the character being in motion. Like how Mac's second hit of Ftilt often misses when you pivot ftilt. He's sliding too far too fast for the second hit (which happens to reach farther than the first) to connect by the time it comes out. This also explains how Bowser's Side B whiffs. It will only whiff if he executes it at point blank during a run. His dash grab doesn't have this issue because dash grabs (unlike side specials) are designed specifically to be performed while running.