[eluser]Nick_MyShuitings[/eluser]
They have been slow lately...
I'm not sure your question is 100% clear, but if you just need to reroute anything that is currently directing to user/username then you'd do it in routes.
I have a setup that does something similar, user/username is the actual path, and if the person wants to enter it that way they can... but I modified the system so that prior to throwing a 404, it checks if the path entered example.com/username is a valid username.
Theres got to be a better solution, but at the time I was just playing around with the concept, it never went to production and subsequently got ignored.
Another way that should work would be the following:
1) In the example.com/controller/method/username you could do a redirect to example.com/username
2) then in routes at the very end you could add $route['(:any)'] = "controller/method/$1";
But that would essentially eat your 404 detection and send any non existent page to the users controller which would show a "user not found" bit.
Third option: Mod your routes file to also lookup routes in the DB. This is what I have working, and in that case you could actually make more specific routes that won't catch all your 404's. ie: $route['nick'] = "users/username/nick";
