Oh the base game is crap, there's no denying that. But it's built to be expandable like MCM2 was. All the real content is user made and downloadable. Very detailed bike models, graphics, gear, objects, and tracks are already made for it. But you need a good computer and the patience to deal with adding it all together, so it's not for everyone. I don't think anyone is making the claim it's just like being on the bike, but it's by far the best thing running in terms of MX games right now. The SX and national replica series are run very well.
With the amount investment it takes to create a game for the new generation consoles I just don't see anyone spending the coin to make a good MX game. Blackbean made that MUD game but it's pretty bad. That would be my definition of arcady.