I like the idea of morpher/transformer job. Reading through posts, I had some ideas on some topics:

Elemental transformation
I can see this to fit with Elementalist job, if it ever comes, as 2hr ability(or whatever similar they're going to introduce). I don't currently have any clear visions about it, but feel free to add to it.

Beastmaster
I'm hanging between wanting it to be a job or a class, but definitely we need one. Maybe I'll choose to favor job route as all classes must have funny names in FFXIV :P. Also I don't think there needs to be a link between BST and Morpher unless job > adv.job is implemented.

Morpher
I would see this to be fit to be an alternative to BST branching from same class. I must confess, I'm utterly confused about specifics for this kind of job. Like skills outside being morphed, how to gain morphs and morphing durations to name a few.

Just some points to feed the conversation. And of course everything is depatable.