Nearly all the non-heroic instances in Outland are doable as feral healing. However it becomes noticeably tougher in the 70 instance when dungeons require far more endurance than before. In terms of gear, I used to just stack up the int and +heal before BC, but now mp5 items seem to help me far more than Int ever did.
If you are feral, then getting naturalist and ooc is vital. However when you're healing, ooc is meaningless. It only procs with physical attacks, and if you have to resort to swinging your staff in battle, consider your group wiped.
my own suggestion would be to give the 0/30/31 spec a try. You lose mangle and a bit of DPS, but you gain a vast amount of healing potential. Though you lose dps, you can still handle solo PVE no problem and you can still tank fine.