I dont think just because mixing is dead so is TM tracks, of course over the years we get to see less and less original ideas (transitions and PF starts ect) but I've always pushed for a unique kind of visual or driving theme each track to keep things fresh. Sure Unlimiter helps out significantly because years of the same limited editor gets boring but there's still plenty of tracks that can be made without it, maybe if people stopped trying to impress everyone with new track transitions and just build what they want they wouldnt be jumping over to Unlimiter or nothing. I used Unlimiter for pretty much strictly scenery mixing but I can live without it.
While we might lose Unlimiter, we are getting the true no limits on TM2 with block creation so how that plays out in TM2 has still yet to be seen... having looked at Hawk's stadium2 custom objects preview what's coming is exciting... for RPG tracks which I personally can't stand but I'm still eagerly waiting for a more community wide accepted title of extra pieces, maybe if we get enough good ones we can get a supported patch into TM2 itself, kind of like how StarRace was added to United and it was all user created tracks.