But isn't this the whole shtick of the M+ system? The infinite scaling? Even that Shadowmoon Burial Grounds will sooner or later change into trash one shooting people nightmare if those hardcore players push the key far enough, so it does not matter.
The 8 dungeons should have roughly the same level of tuning, but if they should all be on the Burial Grounds or Life Pools side - it's Blizzard to decide