I'm not a particularly good healer, but I found AST to be barely more difficult than the other healers in 5.0, and not at all in 5.1. The class can do everything it needs to do.

I personally can't stand it. But if you like it, there's no reason not to play it.

And as a bonus, you get to be the rare special unicorn of healing jobs. It's always fun to like something other people don't.