So the theory was that endermen spawn at the back half of the island when you arrive, then teleport to the lit up area when you walk over to the farm side, then hang around while you are in the farm.
I see what you're saying now! Endermen tend not to teleport if not provoked, but it could become a problem from time to time.
However, that doesn't matter, as you are right, its 128 blocks away so they should despawn anyway. It just seems the farm has low rates.
Yeah, it's an unfortunate side effect from the new endermite method The endermen spawn much more quickly, but need to walk the travel time to reach the drop.
Given all that, feel free to change it, but maybe not torch-spam, maybe something a bit pretty?
I was planning on making the area around the portal pretty, with trees, gardens, buildings, etc. I'll probably have to torch spam elsewhere, though :/
There used to be something here..