IAS jewel might be useless. check the merc breakpoints here:
http://diablo3 [dot] ingame [dot] de/diablo-2/calculatoren/angriffsgeschwindigkeit/?lang=en
Cham is good if you can find it, shael if you can hit the next recovery breakpoint. Not really too many fantastic options otherwise. You always have minor upgrades from things like MAL rune in helm (MDR) SOL (DR) or DOL (life rep).
Other thing to consider is the 1k treachery...I have a merc with 1k treachery and it takes a while for him to get hit, sometimes fade wont activate as much or it runs out. It's ok when I do council runs because the hydras hit him no matter what.
This post was edited by bboynaki on Jan 11 2015 02:39pm