The big problem with Pit in my opinion is that by having a reflector he pretty much automatically outcamps you (although he would anyway with his arrows, haha) so that you have to approach, which Link sucks at. Pit is usually ungimpable, unless he gets dumb. If you hit him out of WoI he can't use it again (I think he can still use any jumps/glide he might have left though; what do you know, Ryos, haha?). Personally I hate Olimar. I don't understand how he works as a character at all, it's so annoying. I don't know what to do against him. Fox is also pretty tough for me; I prefer to fight Falco over Fox, honestly.
If you're gonna play Link, you learn pretty quick how to make the most out of what little you have in terms of offstage game and recovery. Well, and DI, since that's kinda a huge part of Link's recovery.
I've been considering picking up Peach as my actual secondary since I think I'm pretty decent as her anyway and she does okay against a lot of Link's bad matchups. Plus, that way I'm not using a top tier character, haha (although Diddy is a lot of fun to play as). I like Wolf but I get worried about auto-losing to a Dedede if he and Link are the only two characters I play.
tl;dr: Pit's tough but I hate Olimar and Fox more, Link's recovery is bad so you have to make the most of it, I wanna try seconding Peach.