If I run 4 verts I almost always have someone open, usually the slot WR on the strong side of the field. That is on AA with no sliders though.
When I cranked it up to Heisman, this was not an issue either (no sliders).
I'm offline dynasty only, so for me, I just made a house rule to not run 4 verts. Fair enough. But I can see where online this would be a pain in the A.