I don't think the reviews are going to really hurt sales. Sadly the expectations are any movie based game - that is a game launched to coincide with a movie regardless of if it's telling the same story or not - will suck. Unfortunately there's a lot of precidents for that and it's generally true because of the short turnaround time on these games. They simply aren't original gameplaywise (except in very rare occasions) and aren't polished.
The recent Prince of Persia game was great too (especially the Wii version) but even with a strong gaming brand, and movie tie-in, it tanked. In fact, the movie tie-in was probably why it tanked.
So even without the reviews people would expect this game to be 'meh'. And I'd expect sales to be quite soft. Tron is not exactly a 'big' franchise to begin with. Most people under 30 probably never heard of Tron. Hopefully the new movie will bring life to it.
Personally I probably will get Battle Grids at some point (it's getting decent reviews) but I've gotten more than enough titles recently, and have a few more I still want (Epic Mickey, Wii Party, etc), so this will have to wait until it's bargained priced. (Sorry James_TRON)