One character I'm playing at the moment is a Shaman. She's fairly good at healing, as she is a Channelling user, as well as Shamans get some Animist Base Lists as their own (I'm looking at you, Herb Mastery...). Shamans also get similar spells to Seers, so trying to find stuff out is quite easy with a Dream Vision Spell.
But my shaman's main ability is her Spirits, as She is more of a Kami Priestess than anything else (The game my GM is currently running is a High Fantasy/Wuxia type game, so it's heavily oriental). She also has awesome meditation abilities.
I've never run a game properly, but my group's GM has been doing this for over thirty years, and has gone through all the professions. There are only 1 or 2 that He won't let people play, as they don't fit the campaign styles, as one of them is an oriental, and one is a traditional high fantasy.
That being said, I've been through all of the rules, and found some truly strange professions, but I don't feel that any of them are too OP for a game. It's just a matter of Setting, and Character Development.