>Originally intended to have sprite and background scaling but got replaced with Master System support because of Pal markets.
>Lack of sprite and background scaling caused Super Thunder Blade to suffer, Space Harrier 2 was good but was not as good as the original.
>8 (A, B, C, X, Y, Z as well as the L and R solder buttons) (10 counting Mode and Start) button controllers were needed at launch.
>Genesis should've had video mixing support for Master System (and later Game Gear) support, also with SG-1000 and YM2413 support in said adaptor.
>Needed 2 YM2612 chips, not just 1.
>Needed to use a 16MHz 68020 so games can be up to 4GB in size, helping the Sega CD (which would be just a basic 2X CD-Rom drive with more ram) in the long run.
>Needed 256 sprites and 64 sprites per scanline, not 80 sprites and 20 per scan line as the lack of built in Master System support will allow more sprite ram.
>Built in Master System support limited the background layers to 2 with only 1 window layer, without master System support it would've done 4 with 2 window layers.
>61 out of 512 colors on screen was strictly because of Master System support, without Master System support the color pallet would've been 481 (240 for sprites and 241 for backgrounds/windows) out of 32,768 colors, 15/16 color pallets with transparency.
>4 players out of the box, not 2.
>256KB of main ram, 128KB of video ram and 128KB of sound ram.

It’s incredible just how barebones it is in hardware. You beat Sonic 1, 2 and 3 and Knuckles and you’re done with it. While thats not the entire library (see Revenge of Shinobi, Streets of Rage 1, 2 and 3, Monster World 3 and 4, ect.) thats all people care about it.