Lawd. Dissing Logan's fighting skill on this board can get messy. Just letting you know ahead of time.
Honestly though, Colossus suffers from that same thing most X-Men do: We get told and told and told how they do, what is it, 6 hours a day in the danger room, 5 days a week. We're told how much training they do, but outside of someone like Claremont, it's rarely shown.
If we were to take them at their word, Colossus should be a really tough fight for the Thing. He might even take a few wins. The problem is, we can't take them at their word because we rely on feats.
I really wish they'd just have the occasional panel where someone like Wolverine (or someone better suited if you prefer) is the instructor and they're just like "Character x, you've graduated to black belt in x martial art". It would save panels, and would get the point across.