There is no way he is going to be lower than B/B+, Marth's arch type just doesn't allow it, especially in a game where aerials/knowing aerial spacing/hit boxes are almost everything when you want to succeed at high level. They intentionally designed him to have range and control distance, they even gave him a tipper mechanic. This very meta game has been catering to Marth and his aerials ever since Melee. He get's a small range nerf, so what?
I'm willing to be money he still out aerials more than 75% of the cast, just because of his speed, range (nerfed but still) and mobility . Still don't believe me? Look at Sheik, Fox , Falco in Melee, those characters are godlike, and they have something Marth has.... Godlike aerials, speed, and mobility. (same with Meta knight in brawl and various others) Marth has had (or has almost had) unparalleled aerials in the last 2 games, with a slight range nerf in Smash 4, still no way he's going to suck, rest easy true "loyal" Marth players. If you wanna cry about it, go play a top tier when the game comes out.