As mentioned in the Lukaku thread, i think that if Lukaku is made the undisputed No 2. And we can get out of the torres shadow, then it wouldn't hamper his development. We have 60 game + season next year, and Lukaku would get a lot of sub appearances as well as starts when we rotate. No matter how good cavani is he wouldn't play every game. Provided Lukaku is given the no.2 role i don't see a problem. Though if he stays and we still have FT as a supersub, then it could be hampering his development.