Ugh... I hate to say it, but I agree with Blaziken. If they remake G/S I'd rather see it on DS or another gameboy than GBA. The Advance collection is far too large already IMO. DS would also mean that G/S would be better than ever - graphic and music-wise.
I'm kinda biased towards GS, though. Overall I didn't really like them, and the only one of the collection that meant anything to me was Crystal. Looking back on it now, travelling back to Kanto was cool in theory but actually playing through it felt like a lag. I would have rather them spend more time developing Johto than stick Kanto in there, or at the very least have given us an updated Elite 4 after you beat Kanto. It was harder to level up in G/S than it is in R/S, and that's saying something >.>