Why the experience nerf

[WarBlade]

So for sure the reward has been changed, because before you would go to at least level 26 from 23. From other reports, it does indeed sound like it gives exactly one level whenever you do it.

There's a cut off point somewhere.

I just did the Nightmare Ancients with a level 76 Elementalist Druid. Rather than getting exactly 1 level, per other reports, he instead gained exactly half a level.

I expect this might be a contingency plan of sorts to stop high level Ancients exploitation. B)