MVP seems to have the same problem Matt Hardy does...and no, I'm not talking about a weight problem, although that is part of it...it's they're they are just solid, enhancement workers.
Both stay perpetually over despite not winning a lot of matches or taking part in too many memorable feuds (except with each other...and we're talking singles, not tags...and yes, Hardy/Edge is an exception), both are considered adequate on the mic and in the ring, both are students of the game...but that's it. Neither quite has the look or it factor of other main eventers (CM Punk is the ONLY one who is currently deviating from that pack, having a unique look and style). But that's fine...not everyone is meant to be a main eventer. Hell, Santino Marella is probably one of the quickest guys ever on the mic (his quips are so fast and funny it's almost hard to keep up when he gets rolling) and has actually shown some ability, but he's a comedy act, he's comfortable in that roll, and that's probably all he's ever going to amount to. Not everyone NEEDS to be a main eventer, and some guys, like MVP, Hardy, Shelton, Regal, etc, just aren't meant to be one...everyone has a place, but it can't all be at the top.