But dropping omnipotence is the Problem of Doing Anything You Want. Dropping omniscience would be The Problem of Knowing Everything (or Anything). Those are distinct arguments.
The Problem of Evil drops benevolence.
No.
Look again at Epicurus's thingy:
If God is willing to prevent evil but unable,
then he is impotent.
If He is able, but unwilling,
then he is malevolent.
If He is able and willing, then whence cometh evil?
If He is neither able or willing, then why call Him God?
Notice, actually, that the first solution Epicurus offers to the Problem of Evil is
indeed dropping omnipotence. Only in the second line does he offer dropping benevolence.
It just turns out that dropping omniscience is another solution (perhaps God just didn't know
how to prevent evil?)
The name of the problem is always "The Problem of Evil" regardless of whether it's omnipotence, omniscience, or benevolence that's dropped in the deity's attributes because it's always the existence of evil that makes the contradiction apparent.