I think another thing to consider here is the 'Must'... the story side of the power.
Throw a requirement in there for a directly related High Concept, and most of the issues go away, from my perspective. In my game, no way Merlin gets this power... maybe the lowest version (but frankly, he's got better things to do with those points). Narratively, there's no justification for it. He just hasn't been around long enough for anythign else. Most of the entities that have been around long enough for the highest levels are Plot Drivers, and NPC's to boot. I just don't see it as an issue there at all.
This really needs to be one of those powers that a character's story is built around... and I, for one, am a big fan.
What about 2, 5, 9?
That seems like a decent cost spread.