Seems like two different things are being talked about here- visual effects and stylistic decisions.

To the latter, I would argue that the characters in the prequels were part of the elite, the upper crust. Everything looks crisp and new because they can afford crisp and new. The OT follows impoverished farmers, fugitive smugglers and other (according to the establishment) lowlifes. They're not going to have the same brand spanking new ships and clothes that the upper crust had decades earlier.

Also to the latter, I don't understand why this is a problem. Lucas intentionally set out to push TPM as far away as possible from the aesthetics of the OT so that he could have something to migrate to over the course of the films (color pallettes, production design, costume design, etc). It's not just that he used CG (even non-CG elements have this same "new" look at times) or that he used digital cameras (Ibid TPM, shot mostly on film), it's that he wanted a different look for a more elegant period in the galaxy's history.