Classic console versions ran stripped down versions of the PC iWAD files.
I.E. On the Sega 32X, the enemies are missing sprites so that they are always facing you.
Likewise, you'll notice that not all levels are the same. Some have been made shorter, the enemy count reduced, etc.
Perhaps by removing some Flats (floors), using DeHacked to remove enemy bodies and playing the game at lower difficulty levels the game could be sped up enough to play at a decent speed on the 600. Not a project I'm willing to undertake, but it would be quite easy to pull off and perhaps worth it to those who are not so anal when it come to the DOOM playing experience as I am.

Though I will say, growing up, I've had plenty of fun playing through various console renditions.