I just watched TPM and AOTC ( the Phantom Edit versions) yesterday, and I must say, AOTC is aging horribly already. TPM, like you said, is faded looking, and has that pink tint, but it actually holds up well in the special effects and sets department, a bit of colour correction and it'll look great.
That picture of Dooku on Geonosis up there is terrific, the rock reminds me of Egypt now, and looks convincing. That needs to be done for pretty much every scene in AOTC. The special effects mostly look horrible, and the sets are very obvious green/blue screened (I can often almost see the mattelines around the actors, it's disgraceful looking). Jar Jar looks better in TPM than he does in AOTC, for instance, he looks very CGI in his movements, wheras, annoying as he was, he looked more or less believeably "there" in TPM.
The scenes on Kamino are almost hilarious, you've got Ewan McGregor looking completely uncomfortable and awkward, as he's meant to be sitting in a room, talking to a character, when you can easily tellhe's sitting in front of a bluescreen, talking to thin air. I actually felt embarrassed for him, to be put in such a situation (it definitely affected his performance as well, he was very unsure-looking in the scenes).
I've not watched ROTS in a while, so I don't know how it's aging, but I see it having the same problems AOTC has, after only a couple of years, though to a lesser extent.
Seems that TPM will ultimately age the best out of the three prequels (in looks department anyway). AOTC is going to need some serious amount of work to hide the shoddy effects that appear in almost every scene.