So to get started on matchup discussions, lets talk about Marth.
I think that Pit's wing cancel buff really turns this matchup around. The push of his up B far outranges every one of Marth's moves. And with the new Marth being a more offensive based character (who will be approaching a lot) this really hurts his game because of the shear distance he is pushed. And of course, with the little lag wing canceling has, you can punished Marth's whiffed aerial with a move of your chosing (I like dash canceled jab->jab traps)
Speaking of Marth changes, one of the largest changes that Marth will be recieving is the removal of the invincibility on his up B. This means that he will be more susceptable to Pit's many, many frame traps and have a much harder time with close range combat. In a sense, you could say that the zoning game completely turned around, with wing canceling constantly screwing up Marth's spacing and creating the openings needed to get in, and Pit's close range game locking him down once you're in there.
This isn't to say that Marth doesn't have his strengths. Marth has an absurd combo game now, getting combos that can do 50%+ if he spaces his aerials right (fair sends up now
). He's also got very fast kill moves (d-smash now kills, f-smash kills EVEN BETTER, and nair kills), though they'll be hard to space against Pit. His bair is now a real problem for Pit with the angle it sends you at (and since it outranges glide attack, and comes out fast, can be combo'd into, ect.). If your not careful it could just plain kill you, but with good DI you should be fine. Marth's ledge game is really, really good against Pit...until you ledgehop wing cancel
(told you this move is too good). He outranges all of Pit's aerials, he can punish a getup or roll on reaction, and yet a simple push is enough to get onto the stage.
Now for Pit's strengths.
First of all...there's camping. Marth will have to approach you, which is always a nice bonus (especially since you can mess up said approach). You won't be landing many arrows against good players, but it can help you reveal some of their bad habits (defensive players will shield them a lot, aggresive players may double jump over them a lot, ect, ect) for you to punish later so take note.
Second, frame traps. Once Pit manages to get in close he's got a variety of moves just to mess with Marth. You can crossup his shield with a nair and then jab, d-tilt or f-smash behind you to stop an OoS attempt (or grab if you think they'll hold their shield), if they spotdodge the jab or d-tilt then you can hit them again when it's over, if they roll behind you you turn around and do it, and if they roll away you push them closer to the edge with a wing cancel and do it again. Frame traps are fun
Now against Marth they might not look so good right now (since he's got up B), but once that up B invincibility is gone then he's trying to outspeed Pit...which is something Marth simply can't do. So you'll be getting a lot of pretty much free mixups (jab->grab anyone?) since many opponents will be too afraid to hit you out of them (and rightfully so, Pit is a walking frame trap). It's too bad that Pit lost a lot of his throw options though <_<.
Point 3, edgeguarding. Arrows forcing Marth to go down, mirror shield wrecking anyone who doesn't sweetspot pefectly, up B pushing them out of sweetspot range....Pit's a *****. And even if they do get back on the ledge, Marth is not particularly good at getting back on the stage (you can push him back off with wing canceling funnily enough). With Marth's new fall speed he'll be forced to up B quite a bit. Though it is gonna be buffed in knockback and perhaps get a larger hitbox, so I'll hold my judgement for now (arrows still **** though. That one arrow that finishes a combo really hurts Marth's momentum based recovery)
More later <_<