The Tavern

Let's be honest - this is not "incredible sacrifice". Losing two levels does not impede your character, yet it gives a huge amount of piety. I think piety gain from that sacrifice should be nerfed to "moderate", around 15-20. Or the sacrifice itself buffed - instead of losing two levels, you instead gain new levels much slower, and then it decreases your current level retroactively, as if you played with this debuff from the very start. Then it is worthy to be maybe a major sacrifice.

I agree, I almost always pick this sacrifice if it's available. Though I guess it's possible XL is actually more useful than we perceive it to be?

Sac experience is kind of weird. It's often a big drawback right when you take it (going from xl 5 to xl 3 immediately reduces your max hp by a little more than 30% iirc). However, because the experience cost of the next xl increases with xl, you can catch up very quickly. The sacrifice does nothing from that point until lategame. Most of the xl loss penalties are also directly affected by other ru sacrifices. There are ru sacs for frail, -MR, and lowered stats for example.

If ru mutations are supposed to be impactful all game long then sac exp does a pretty bad job of doing that, imo. Maybe slower xp gain all game is different enough to be worth pursuing? I don't think I'd take the current version very often at 20 piety.

Should just apply -2 to your experience level wherever it's checked instead of screwing around with experience points to apply the effect.