Then there's the 90% of useless combat skills that just didn't scale well enough to be used after normal difficulty. Again, you couldn't really know.
Sure that's fair. It's going to be a long time, probably years before someone can fully compare the skill subsystems of D2 and D3 in a meaningful way. For now though on the surface you get a lot more actual "skills" although I'm grouping rune variations on skills but less freedom for building a unique character which is important to some people. Hopefully the itemization will help this somewhat although most skills seem based on weapon damage which seems to homogenize things quite a bit.
Playing: Xenoblade Chronicles DE, Ys IX, God of War
Watching: Lupin, You me and the Apocalypse, Days of Thunder