Actually none of the versions for other systems have good graphics.
I played the Master System version back in the day, and I never pass the first level.
Anyway, back to the NES, Here's my redemptions of the sprites, using the same sizes.
I've spent more time on Bart, that's why it is more detailed. You can compare with the original (also Moe). One would think it's not possible to make such graphics on NES because the color limit.
On NES you have 3 colors for each sprite tile, and you have up to 4 color palettes, total of 12 colors for sprites
You can use one palette for each tile (not need to stick with 1 palette for all the sprite), that's what I did on Bart Sprite.
Do not believe? Download the ROM (zip file) and test on NES emulator! It's my first sprite test I'm releasing on internet.
Yes, I'm coding for NES now.
Bart moves from left to right and that's all.
EDIT : Added Krusty, Milhouse and Marge sprites on NES ROM. Note Marge sprite is not the best of the bunch, but it is colorful as the original.
I'm surprised how many sprites NES can handle, I've used 40out 64, there's plenty of sprites to use yet.