Marth can probably still do most of what he could do before, just in a more low tier kinda way. He was kinda like this in the E3 demo, basically just a worse version of his old self. Remember what happened to Jigglypuff in the Melee to Brawl transition? It's too early to be sure, but I'd brace yourselves for Marth being the same this time (maybe not quite as brutally wrecked), and I struggle to see how Lucina is going to save the moveset since he's still a spacing based swordsman no matter how you slice it, and having no tippers is just a bad thing. It's okay though; not every character can be a winner, and if Marth is the unlucky loser this time, so be it. He wasn't more deserving of high tier than any other character, and from what we've seen and heard so far, there aren't a lot of characters as unlucky as he is.
That Pac-Man clarification is interesting and kinda in-line with what I was expecting from the earlier reports. The description of him having "quirky" movements likewise is encouraging that his mobility may not be so bad, just different. Like in Brawl G&W's movement parameters are not so good when direct compared to the important parameters on other characters, but then he has this special ability to decelerate in the air really, really fast that effectively gives him great aerial movement once the player figures it out. I'm hoping Pac-Man is the same with "quirky" meaning he has some non-traditional movement parameters that average out to good in the end.