User blog comment:Deshiba/The Ghostcleaver/@comment-9048637-20140313183057

Err, Youmuu's and Cleaver already stack. The unnamed Unique passives only stop the same item from stacking. So, you can't stack multiple Cleavers (any more at least, hurr hurr) or Youmuu's...s... err, Ghostblades, but you can stack one of each. Just as you can stack Frozen Heart and Iceborn Gauntlet for CDR, despite them both building out of Glacial Shroud and getting their CDR from there, but you can't stack several of either for the same purpose.

I'll probably address the overall point later. I just wanted to throw that one out there quickly.