Olver is a incredibly shifty player out there. He's got incredibly on-ice vision, and he has creativity all over him. His puck possession skills are top notch. Top notch playmaker (in college anyway).
The major knock on him is his size (he's probably Hensick sized). He's never played a defensive role before, but he does play with a lot of heart, and he has an ok defensive game, though it's not his area of strength.
I don't think we have a true bottom 6 though. Our 4th line is likely our crash'n'bang line, with the 3rd line being a more physical scoring/hard to play against line than a true defence first unit. Each line has defensively responsible players and the way the NHL is going kind of renders the idea of a top 6 scoring and bottom 6 defensive obselete, to a degree.
I was at the Dallas game Tuesday night and this kid looked GREAT. He looks like a great 3rd/4th line player and possibly 1st/2nd if we are plagued with injuries. He was all over the ice on Tuesday and had an amazing fore check. Very skilled with the puck along the boards and created several good chances all night long. Also, he was playing with McCleod and Winnik (I think) and he still looked like he was dominating all game long.