I got cheated by it rogue becoming NINJA. And not THF. So a dancer would be my second choice to switch my main class from Warrior. Which I've been playing for to damn long and don't find it as fun anymore. However quick ques and my time means something to me is why I keep playing it.

Sam no interest in.
Red mage also very little interest in.

Beastmaster would be fun. But I don't see anyway of it working in FFXIV. It would be to similar to SMN in my mind the way they are currently doing things.
Bluemage the game would need to be reward to much to make it fit. O you don't have XXX ability because you never learned well you rotation is broken without it.