Sapphire maybe. Gold/Silver/Crystal definitely not, it's unnecessary.
Why do you say that G/S/C is not necessary? Is that due to the bug/exploit that allows you to change the clock and the remake for the DS?
The biggest deterrent I have from putting a lot of time into my origional games is the fact that the IV vals are a max of 25 and the pokemon doing wierd things if you find a way to get them into the GBA(3rd gen game) and then pal park them.
The save files on my R/B/Y + G/S/C are left over from when I was playing as a baby. I still have them but I play the remakes more, due to the vastly improved quality. Back light screen on the SP and rechargable battery deters me from using my GBC (yah I know GBC cards work in the SP)
I think there is a way to get pokemon from the 1st and 2nd gen games into the 3rd gen games. It involves pokemon stadium (either 1 or 2) can't remember. Never done it myself. I was reading about it online though. I know one problem is that in the first two games there was a programming error or something, and the max IV values were meant to be 31 but somehowe (maybe it was simply a typo a programmer made) the final build of the game had them set to 25 and that is what shipped on the final cards. I also don't remember if they didn't notice until they sat down to code the 3rd gen games or if they kept G/S/C at 25 to ensure compatibility. Probably at that point in time they were thankful to be making a second serries of games, and it was easier to just use 25 again. Either way I have seen an article or read something about someone who got gen 1 and 2 pokemon into her 3rd gen game and they were problematic due to more reasons than bad IV values. They were also a lot weaker as when they were created their IV's were only rolled for values between 1 through 25, unline all the pokemon from third gen to current whos IV values are rolled for a number between 1 and 31