I quite like the idea, but stepping away from the technical reasons, i think from a neutral point of view it's not something i am likely to use, nor can i see my friends using it or anything similar. There are just too many other options, the big 3 of youtube, vimeo and facebook just have too much of a market share and are something most people are comfortable with.
I know my friends likely wouldn't use it as they are complete beginners and would find it a bit intimidating putting fun edits of them mostly decking it, just starting to link turns etc when every other video on there people are popping corks, hitting kickers and the like. I suppose it depends who you want to attract.
As mentioned i've always thought sites like these have to be kept simple (like yours is) but also offer something NO-ONE else does, a quick idea would maybe get someone qualified (instructor, pro rider etc) to offer some feedback on the riding in the video if requested.......i dunno just try and get something unique.
I could be talking complete b/s but it's just my point of view