A demo to a Trackmania game would either be shitty if they don't allow user-created content, or identical to the main game if they do allow it.
A demo without user-created content would be *absolutely fine* and just what people would expect. When it comes to content, demos are pretty much *supposed* to be shitty by comparison with the retail product. No one would ever buy the games otherwise. The whole idea is to give enough of a taste that they want to pay for more. I'm pretty sure this is obvious to most people.
Include a small handful of decent tracks so the player can experience the handling/gameplay of the Canyon car and environment, see how the new graphics run on their machine, etc.
Nations is obviously going to be somewhat indicative, but it's not a demo version of Canyon.