The character movement is REAL slow. Even slower when you hit the 'walk' key (don't know why Legend even gave us that option.) I've heard there are speed hacks, but I feel that goes against the wishes of the designers, even if they were wrong on that point.
And try playing single player after XMP, you'll feel even slower. I play as Gunner, and still feel like I'm crawling in sp. I also keep hitting the 'walk' key, because that is my 'sprint' in XMP.