Would such monster fit as a replacement for Mastermind?

If yes, then i can try to make it in Blender and then make proper sprites.

Possible changes: remove convolutions (to make it look less like Mastermind), replace cameras with actual eyes, maybe even replace the brain with one big eye.

Edit: tried to make "less sketchy" sketch:

I think that the original idea was to "swap" the Cyberdemon and the Spider Mastermind, conceptually. I.e., the Cyberdemon replacement is an assault tripod piloted by some brainy creature, so the final boss should supposedly be something close to a cybernetic organism then.

Perhaps some giant humanoid creature standing on all fours, with cybernetic implements and a cannon mounted on its back, with some nasty alien thing piloting it? Or maybe a leviathan stitched together from many creatures and cybernetic parts? There are actually many different directions it could go. It could be another of those insect-like things like a trilobite, with cybernetic parts, to continue the design theme of the many ordinary monsters.

I just feel that the brain-tank design is a bit too close to the Spider Mastermind.

4 hours ago, MrFlibble said:

I think that the original idea was to "swap" the Cyberdemon and the Spider Mastermind, conceptually. I.e., the Cyberdemon replacement is an assault tripod piloted by some brainy creature, so the final boss should supposedly be something close to a cybernetic organism then.

I think a cyborg dinosaur with a gun would fit best. Something like this toy here.

Actually yes, something along those lines.

Someone with a better imagination than me could probably come up with something cyborg-y enough and possibly looking "eldritch" at the same time, instead of a straightforward dinosaur.