SRB2, you're quite ignorant on cartridge size. Remember, time has passed. A LOT of time. Henceforth, cartridges are a ton better than the old days.
Sonic 1 is on a 512 KB cartridge. Sonic Advance 1 is on a 8192 KB cartridge. I don't pay attention to ROMs, but I'm sure there are 16 MB and 32 MB cartridges for GBA. They have a TON more room than in the old days. Hence the prevalence of voice samples in GBA games. Hell, I have a GBA game with a FMV logo and one song with vocals. Sure, it's not an MP3, and is low quality, but it is a real song on GBA.
The GBA is superior to the SNES and Genesis in pretty much every area except the sound chip. Everywhere else, the GBA excels.
So no, GBA would have no trouble pulling off the Sonic 3 trick. Wouldn't even break a sweat. In fact, if they did redo it, they'd probably do a much better job with the GBA hardware.