Some theologians and philosophers would say that religious devotion to anything less than a perfect being amounts to idolatry, and a less-than-omniscient or less than omnibenevolent or less-than-omnipotent being would be less than a perfect being.

My own view is that this is a view that only someone in the grip of a theory could love. I rather doubt that most believers give much thought at all to the difference between omni-God, as it's sometimes put, and a being so far beyond us that, perfect or not, deserves their profoundest devotion. (Whether there actually is such a being is a separate matter, and not the subject of these comments.)

Perhaps there's one exception. Perhaps a being that was less than morally perfect couldn't be the object of a non-idolatrous religious devotion. That's a subject for an interesting conversation, but I'm not convinced that even this is right. So I think your question is a good one, and I"m inclined to think you're right.