I don't want argue with you, but it did take you an awfully long time to realize the subtle workings of melee; where as I've been playing this game for a little under 2 years, now.
Regardless, you can't base how good Marth is simply from his throws and how much camping pisses you off. To me, that simply states that you don't have the patience to learn the differences between these two games we play. His grabs, not as good as in melee, no, but about the same range and usefulness when it comes to mind games. Also, the best approach to camping, Ive noticed, is to attempt to use all your patience and ignore it. Just because you're losing is no reason to change your view on the character. Marth seems like he's not as good because everyone knows how to play against a Marth, and you've found that with the subtle spacing changes that you're not nearly and precise as you were in Melee.
That doesn't change the fact that Marth's back air kills at semi high percentages, as do every single one of his aerials, hold the neutral. This game isn't entirely what you think it's about if you're still trying to go for grab to juggle combos. I mean, have you seen the smash DI sensitivity, or even the mechanics of the air dodge? Grab to attack doesn't work anymore, and that's going to mean a lot less stock taken by down airs, but the simple fact that you can still Ken Combo with proper dash cancelling is a good sign that you can't find another explanation for why you're losing.
All Marth's attacks when spaced properly, which is all that matters, are quite a bit stronger than in melee, with more stun, and more chance to kill. He also still maintains the ability to pressure with his aerials, since for some reason, someone thought it was a good idea to make his back air not only stronger, but faster. So he can short hop back air forward air? And he's not as good as he was in melee? What about the full jump double up air? Or how the tippered up air will usually kill someone off the top at 95% or higher?
Come on man.
EDIT: I forgot to mention how much easier it is to gimp someone at low percentages using his forward air as an edge guard, and utilizing the auto sweetspot with the up b to steal the ledge from grapplers. Oh, and the up b. Oh god the up b.