I like the CGI, but an interesting option would be to recomposite the effects.

It’s time consuming, but you can mask each element in separate, and them apply some filters. For example, you can add some bloom to those star destroyer lights, engines, etc. Create some depth of field, add shadows, etc.

So for the falcon departure, I’d try to keep the original model, but change or improve the planet.
For Tattoine I’ve seen great photos of the actual filming locations, taken from similar angles, so again perhaps you could use those to reassemble some effect shots.

Getting the CGI anywhere close to the level of the original models might even take longer.
Once I tried to better Star Trek TMP’s Enterprise… well it started to look similar with about 12 lights… and 2 hours to render a frame… But it never looked better!

Anyway, good luck!