The Ideas sounds good.
I have an ad idea to the dogs and to some wall textures.
The snes version features only a few walls and only one version of it.
For Example the Cage (orginal without skeleton) Idea is to give the game a rougelike feature. everytime you start a NEW game some walls could be different. The same with the Dogs/rats or even the doberman watchdogs from those spear of destiny return to danger games.
its no must have its just an idea
Weaponswitch would be nice because this orginal solution makes a feel of not full control but with free switch it would be perfect.
about the Faces, i try to get all faces snes ready.