I answered FFVI on the poll because I remember Relm's ability as being one of the most unique among the varied cast. However, I have not played most of the games you mentioned. I like using blue mages on the FF tactics games, one of the most entertaining jobs to have a character learn. Most of it's attacks are very useful. It has no real one-turn, one-hit kills because Roulette randomly selects a unit on the field which can include an ally unit, and Doom takes three turns to kick in. Cornered is very much a one-hit kills move, but your blue mage has to be at 1 hp to use it. FFTA had a move called Twister that would halve the life of all units on an area, but it got removed (along with Goblin Punch) from the ability list in FFTA2; it was one of my favorite moves.