The bonus accuracy and perception from tactics are excellent if you plan to PvP (never hurts in PvE too 
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cant go wrong with it in pvp 
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Well, I'm not sure on Fire/Empathy's endurance...if it's good, go for it
Leadership powers are the Super Set of the mastermind, a */FF with no attacks can have defencive toggles from the power pool sets and all Leadership powers on, with no stamina, without losing endurance.
I have just respecced out of the leadership pool on my defender and I believe the bonus is less on a controller. May be useful in PvP but in PvE I found it didn't make much difference post 30. Most toons have enough accuracy and damage by then anyway.
In PvP (I have only done a little) I found that Tactics didn't help me see stalkers that much better even 3 slotted with Acc on my defender - though I would say that it did save me a slot in Accuracy on my blasts ( 2slotted not 3). Maneuvers and Assault I saw no difference when running, I took them then removed them from the tray after a few hours of game time. Maybe with a few teammates running these too, which might be likely in PvP??
Most useful power in PvP I have found was the temp power Wedding Band found in Striga. I managed to stay upright against a Scrapper for at least a minute in warburg. A stalker couldn't one shot me with this on but could easily if I was too slow to activate it.
Have got leadership with my controller as i have solo'd a large amount of the way up to 34. find that tactics is a very useful power to have on when im solo'ing missions with +2's and i NEED to make sure they are held. although i dont htink it is an absolute must and dont often have assault on, it is certainly useful if you have the spare spaes for the powers.
IS the Leadership power pool worth gettin for a fire/empathy troller? any suggestions welcome please. =)