This looks fine, but people have been telling me uncommons and commons should have lower power level

If this is okay somebody correct me, but i think maybe a 4 drop 2/3 would be better, same toughness, but 4 power is unecessary because it has deathtouch, right? Also it could alternatively be a 3/2 which feels more flavorful and thematic, and would allow it to be taken care of before it kills everything...

Nonetheless, a pretty noticible threat

With this (which should have different p/t) and Bonecrusher Minotaur, would it be fair to ask for a red one? Or does Aguthor's Zealot fill that role?

The power does matter - because it's what happens if you don't block it.

That's pretty much right at the top of the level of P/T black gets at uncommon. It's probably fine; it's certainly desirable - pretty nice aggro, pretty nice defensively for control.

And in the end, it probably just trades with a 3/3 and so it would be very hard to justify being rare.

i think you typo'd but zealot is just an aggro piece, with a possible downside. This guy grows in a nice pattern or eats a dude everyturn. Yes, another red one is coming.