On the unmentionable forum, someone said that Defiance aura is next to useless on an Act II Merc, giving something like 1-5% less chance to be hit. They claimed that the cth-formula is different with Mercs and Defiance doesn't really help them unless the Merc has like 100k def. I wonder if there's any truth to this claim? If there would be, it would probably be mentioned in guides that Defiance is useless, but I thought I'd ask anyway.
Second question is about the +Life on Fortitude; they claimed that it doesn't work for Mercs even though it shows up on the LCS. This was in a thread where it was argued that Treachery is superior on Mercs (even damage-wise due to CB procs and greater attack speed); this third question would require substantial math and/or tests, but if someone knows whether indeed Treach beats Fort, it would be nice to know, too. This ofc ties in to the defense question in that if the added +def from is useless on Mercs, it makes Treachery that much better.