-They teleport when damaged. My logic is that ideally, they'll teleport back to the trap in most cases, so I don't know how important this actually is.
-I've heard mention of them dropping blocks and gumming up the works of mob traps. How exactly does this work? Is it a consideration in this kind of design?
-Is it even worthwhile to have a trap that supports Endermen on the overworld given the ease of constructing one in the end?
What's your opinion on those questions, and are there any other design issues with mass-slaughtering Endermen?