After playing a bit on the PTS, my opinion on Fatecarver has changed a bit. I think fatecarver should be left alone, and it is ultimately good for the game for it to be strong. The way Ossein Cage is designed reflects this. Most of the fights have to do with dealing damage to spread out enemies, which could not currently be done efficiently without Fatecarver. I find the Ossein Cage encounters very engaging, and actually enjoy the skill expression involved in setting up and aiming your beam to hit as many targets as possible, as quickly as possible.
The problem is not Fatecarver's raw damage, but its overperformance in unstacked target scenarios. Take wall of elements as an example. With Maelstrom staff, 1 cast of wall should be stronger than 1 GCD worth of fatecarver, but once it's placed you cannot move it without commiting another cast, which can be a huge damage loss. This is unlike fatecarver, which you can dynamically shift to different targets. As you start shifting to newly spawning targets, the disparity between fatecarver and other AOE options grows much more than it does in stationary target scenarios.
This is a difficult problem to fix; If one attempts to buff other AOE options they could create imbalance. However, I want to raise a couple of suggestions.
1. Remove the 1 at a time limit on ground AOE skills. The ideal change would be that you can stack multiple ground AOEs, but each enemy can only take damage from the AOE every x seconds (where x is the normal tickrate of the AOE). This would stop players from stacking AOEs on top of each other for ST purposes.
2. Increase the length of wall of elements to 22 meters to match fatecarver. Look into giving other dots similar distance capabilities.
That is for ground DoTs. AOE Direct Damage is also too weak compared to DoTs. For unstacked scenarios, it performs very poorly. I can't think of too many things that could start to fix this except buffing/adding skills with ricochet effects. Skills like Ricochet Skull, Silver shards, and force pulse could be buffed to allow for their secondary effects to hit targets at longer ranges.
I think the level of AOE damage provided by Fatecarver is good for the game. However, I think it is dangerous that only fatecarver can provide this kind of output, and I think that Zenimax should explore options to empower other AOE options.