how nasty and.or great is a celestial version of Fiendish Vessel?

[ohako]

So...

Fiendish Vessel, from the Advanced Race Guide, is a tiefling-specific archetype for cleric. There are two main differences

1. You worship one of an archdevil, a demon lord, or a horseman of the apocalypse instead of a deity.
2. You channel evil instead of channeling negative energy. That is, your channel heals evil creatures and (!!) harms good ones, Will negates

among other goodies

How OP would a 'celestial' version of this be for aasimars?

1. You worship an archon, angel, agathion, or azata instead of a deity.
2. You channel good instead of channeling evil
3. ...oh, by the way, your base racial stats bumps your Wis and Cha...

[Goth Guru]

I was looking for a sort of spelljammer. Did you mean Vassal?

[gracefulArmageddon]

No, it's called Fiendish Vessel. :P

And I don't think it'd be all that bad. Maybe more useful from a player perspective, but not more powerful. Don't see why there wasn't already something like that. x3

[John Spalding]

I played one in Shattered Star from level 1 until level 17 or 18. It was a good time. I rarely channeled in combat because the healing was quite small and the negative effects quite weak. I loved the divinations though. For me the trade was worth it.

In my view, it was very well balanced vs. a vanilla cleric.