I so agree. Latest picture post on the JPL website from Opportunity is the newest rock they're boring holes into that just so happens to look exactly like all the previous rocks they bored holes into. It seems logical that, although Fram Crater has a different arrangement of rocks as though the blast was more recent or more violent, the depth of excavation is probably no more than Eagle was. I like you am concerned that something will fail on either spacecraft prior to them reaching the really mind-blowing areas. Endurance crater certainly has that potential to have material exposed from much earlier eras and should be the top priority now.