I need to get out of my old Hive spec. Basically it comes down to one question: How do I slot Assault, Tactics and Vengeance?
Assault is usually just the initial slot with an end reducer.
Tactics is an end reducer and if you have slots to spare, to hit buffs (may be a waste, not positive).
Vengeance is best with 3 defense buffs, slotting the heals or to hits is gravy. On my mastermind, I've slotted it 3 def/3 heal. When activated, it heals up most of the damage I've taken and makes me nearly unhittable.
The benefits of leadership will be less for a blaster, tank or scrapper than for a controller or defender.
I'm also taking into consideration the fact that Recall, Hasten and Group Fly (the powers I'm replacing with leadership) have almost no utility on the STF.
I'm guessing that the to-hit boost that vengeance has isn't as high as it's Def?