Looking over my roster of tacticians, I'm going to make a pitch for my favorite tactician in MAA iOS.
What? Not Emma Frost or Captain America? Yes, you read correctly.
He's a fairly consistent hero. His attack can apply bleeding to enemies. The chain of his attacks is very straightforward. Start with Anti-metal Claws gains Heart of the Panther. Next attack will be Panther Stance, a quick action that gives Panther Stance and coverts the Heart of the Panther into Rage of the Panther and Guile of the Panther, followed by either Anti-metal Claws or Wakandan Arts for a huge double attack on his enemy.
I might stick a Wakandan Arts attack in between my first Anti-metal Claws and Panther Stance if I think there's enough rounds.
Vibranium Daggers is great to remove buffs from enemies or deal extra damage to mechanical enemies. If there are blasters among my enemies, Black Panther will shred them quickly.
Black Panther's two drawbacks are that Vibranium Daggers has a low chance to hit, which can be frustrating, and he's not very durable even though he has high evasion. That means he dodges quite often, but when he gets hit, he gets hit hard. There is also the danger that if he gets his buffs removed after he uses Panther Stance, it will be 3 rounds before he gets to use it again.
Emma is great. Diamond body makes Emma one of the most durable tacticians. Psychic Tap essentially renders enemies unable to attack every other turn. Add a buff that restores stamina and removes debuffs from allies. What's not to like?
The problem arises if your enemy is a mindless, then Emma is pretty much useless. You are left basically toggling between War Diamond and Unlock Potential. For this reason Black Panther is a much more versatile hero.
I don't have the WW-II uniform, so I have to waste an extra turns to use and reuse Shield Guard. He has great survivability over-all and is a fine tactician, but he's boring.
Not much of interest can be said about any of the other tacticians. Each of them has one interesting or useful power, but they're not useful enough for me to consider putting them on my team very often.