>>719008589 (OP)
Actually he liked Muffet so much that he gave her a starring role in the game, an unmissable mandatory segment.
The other kickstarter fanmade characters he shunted into the deep recesses of the game so that no-one would ever be able to find them without datamining.
So clearly he liked Muffet a lot and expanded out her role way more specifically because he liked the design so much