I'm not against a little tuning, and would think it unrealistic to see none of it in the future. Having a few variations of the cars on the track would be good, show diversity, and could adapt differently to each drivers. Having an extra winglet here or there to improve stability for someone, yet some other person don't need it. There's a lot that can be done for racing with tuning, than simple bling. On the XFG or UF1, okay, thats bling, but for example a GTR or SS. Do any of the real F1s look the same (except same team) on the track? No. But overtuning and stuff is definately over the top and I hope to see none, especially those neons.
In short: Tuning for rice = no. Tuning for performance/driveability (yet keeping cars balanced in it's class) = yea, I guess.