Agreed. I was happily playing through until, in the course of a particularly involved battle, I paid too much attention to my enemies and stepped a little too far up and had to go back two rooms. This was frustrating enough that I decided to move on and stop playing.

Hmm, I might have a look at disabling it.

I didn't mind it. At first it caught me by surprise, but then it's just another thing in the room to beware of. I'd leave them there, but perhaps make the danger markings around them a bit clearer (less dirty yellow?)

would definitely be more fun getting killed by a monster than the floor edge.

I don't think it's bad; it makes you have to pay attention to how you maneuver when stuff is getting hot and heavy.