I dont think Rahul can revive Congress in UP at the moment.
The reason is the strong existance of local parties, and the local parties have their solid vote bank. One thing that these parties lack is Glamour... Rahul will bring that much needed glamour in those rural areas and will get benefitted to some extent... but finally its the connectivity that matters; He has to strenthen routes, he has to connect himself to a common man.
Once he is able to do so he can revive congress in UP and it will definitly take some time.. So dont except much from him in these elections