Subtlety, LOL.

It's probably safe to increase the Hemo debuff. We modeled it after the old Mangle and then buffed the Mangle duration.

Rogues might use Hemo slightly more than Ferals use Mangle, but really they are pretty similar: use one for the debuff (or often in PvP) and then Backstab / Shred when position allows it (rarely in PvP).