We have Mundus stones for just about everything but as the game progresses and they continue to raise the CP cap, why not a + experience Mundus Stone? We have them for +Magicka, crit, health, movement speed, etc., so it would fit right in and I don't think it would be hard to for your Game Designers to throw one in.
Now before anyone says it would be an unfair advantage, I don't think it would and I'll just explain my viewpoint as to why. First, most everyone can only have one Mundus active(except the TBS set) so if you choose to run the +experience it would just more than likely be for solo grinding or small group grinds. No one is gonna be running Veteran Dungeon or trials with it on as it would gimp your group. So in that aspect I don't see how it could be any way associated with something out of the norm or game breaking.
Second it would be a small buff like all the other Mundus Stones out there. Say 12% and if you had all Legendary Divines on your gear maybe boost that to 18%
I do not think it would really harm the Developers Crown store sales of Scrolls as I would still purchase them anyway cause they would stack. We already have Ambrosia in the game this is true so if that didn't harm their scroll sales then I doubt this would either.
What do you think community?