Three top level players at once is a lot of rep for most characters. Olimar in his prime had four, Ice Climbers never had more than two at once and Diddy / Snake / Falco never had more than three at once. Marth has no business complaining about a lack of rep.
He's also less efficient and can't cover as many options. He just isn't as good.Marth is actually harder to use than Ice Climbers, Olimar, Diddy Kong and obviously Lucario combined. Physically, mentally, technically and also human hands aren't designed to backwards reverse crab claw to be perfectly efficient with Marth's high tech super spacing.