I've been a Sonic "fan" since I watched AoSTH (in Swedish) when I was 8 or something, and I still enjoy to play both the old and the new games. I actually really liked Sonic Unleashed (PS3) a few years ago when that was released, and when Sonic Colors was released I got a Wii almost exclusively to play that. Now I occasionally play Sonic Generations (PC) and Sonic 3 & Knuckles, but I'm not going to get a Wii U for Lost World, it doesn't look particularly interesting anyway. I also love All-Stars Racing Transformed (PC), though I don't know how much that counts as a Sonic game.
I basically like both the character and the unique gameplay of the Sonic games, but I'm not as big of a "fan" as I used to be, TF2 has been my favorite game since I got it in 2008 and since then I've been a lot more interested in First Person Shooters.
And obviously I've been dreaming about a TF2 Sonic promo for a long time, I think they could probably get away with adding a pair of Sonic shoes for the Scout or something as a promo associated with some new Sonic game release for PC, but until that happens I don't see them doing it.
Good luck on making a Sonic themed map, by the way! All the ones I've seen so far have honestly been kinda shit, not least because the extremely vibrant colors really don't fit into the TF2 style. I think you could make it better by experimenting with some fancy stuff with the lighting and detailing though.