Tron Legacy (Tron 2) is a film I think is going to benefit from being in 3D in the sense that it is set within a world that would be suitable to be shown in 3D.
However movies that are in 3D just for the hell of it, to make a quick buck or to try and gain a wider audience, or a way to entice fans who may have been starting to lose interest to become interested once again is where the overabundance of 3D films will have a negative effect on the industry.