So much of what bothered me about the CGI of the prequels was the way that it stripped out the gritty, organic environments of episodes 4-6.
I remember watching the making of "Rerun of the Jedi" and just seeing all of the work and care that went into making Jabba the Hutt or his sail barge. It was incredible and it had a depth and scope that CGI couldn't replicate.
I think it also effects the way actors act. Part of acting is the interaction with ones environment. If you're standing in front of a green screen for the entire shoot, I'd imagine it gets hard to sell your character.
This post was edited on 5/6 at 2:59 pm