The SNES was definitely more sophisticated than the Genesis in terms of video - total color palette is 32678 colors vs 512. Makes sense as it was released 2 years later.
It was released two years later, but all the upgrades were to more peripheral features like the palette and various special effects. They're both chewing through the same amount of memory each raster to draw the screen, which is the core of what each hardware system is designed around.
It's an interesting contrast with NEC's Supergrafx system, an obscure upgrade to their better-known Turbografx-16, which was released some months prior to the SNES and was a much greater advance in terms of raw power. It uses two separate graphics chips which simultaneously read graphics data from separate banks of RAM, which allows a lot more to be displayed. It has twice the sprites, twice the graphics RAM, and can use up to twice the resolution as the SNES. However, it's not as "well-rounded" a system as the SNES and is simpler in various ways. Unfortunately the 5 or so games that were released for it didn't push the hardware much, so you won't be able to see much evidence of its prodigious capabilities, but they're there.
