It’s not that the CGI is showing its age or that the render engines available today are more capable of realism than the render engines that were used at the time. ILM uses SOFTIMAGE for the vast majority of their model/texture/animation/render pipeline as well as there own scripting tools created in-house. Even if they were using the stock (I use the term stock loosely) renderer (the award-winning Mental Ray) then they had all the tools needed to produce results as good as or better than today’s best animations. It’s not the tool, it’s the artist, and my best guess tells me that they got the best results for the time (read money) budget that they were on. Judging from what I saw in the film, the models were excellent, so you can probably lay the blame at the feet of the texturing and lighting and animatics department for the inconsistencies in the finished product (and I am certain that the ultimate blame would go beyond that to Lucas’s reputation of making changes that suits an over-saturated fantasy world that was rattling around in his whirring tin brain.
Sure, the technology has advanced to the point where faster PC power and software updates make more complex CGI practical, meaning we can do more today than we could before, but ultimately it is just a question of how much time you have to complete the project and how good your artists are. I’m certain ILM’s artists are just as good then as they are today.
The long and the short of it is that ILM could have gotten today’s level of results with the tools they had then, if only given the time and freedom to do so. Time is everything, and at an average rate 0f 20 to 40 hours of render time per frame (depending upon the complexity of the scene) and at 24 frames per second, you can be looking at a month of render time for a single second of CGI footage. And then Lucas comes in and doesn’t like the way Yoda’s robe swings when he begins a leap in a certain scene so those things need to be reworked and then rerendered all over again… You begin to see where a huge chunk of the money in these films go.
And since the prequel trilogy never happened anyway (remember–it was scrapped in preproduction), what’s there to fix?