Is there a specific reference to the movie actually being "different and even longer" or is this being inferred by the McCallum quote? What is wrong with having extra time to polish a film?
I personally don’t feel it is worth getting worked up about. See it on film if you can't see a digital projection, and then see all the changes on the DVD/HD-DVD/BluRay. Digital presentations aren’t all they’re made out to be at this point anyway. There’s strong argument for them after the first few weeks in regards to print wear, but from an image standpoint, a pristine film print will look better than any digital projector in use at this time. The only real standout is uncompressed digital audio.
The only area I see as defensible is where you would like to archive the "original" theatrical presentation (the edit printed to film for May 19) for the future. That version will be lost forever if the current trend continues. But that is also the case for TPM and AOTC - neither are the theatrical versions or the v2 "digital" versions.
And AOTC isn't necessarily a good indicator of what can change in ROTS. AOTC's last few reels were in flux for a long time. The latest word has been that ROTS was locked some time ago, and the biggest issue now is with runtime, and that some of the off-world Jedi battles are looking to be trimmed. It's not like in the film version you're going to see Vader burn up on Mustafar, and in the digital print magical fairy pixies swoop to sing a love song instead.
I’m just curious what it is, specifically, that bugs everyone about the issue.