So long as the best way to control mobs is by killing them and the best way to prevent damage is by killing what is damaging you then damage will be the optimal way to play in a group.
This. The best way to reduce the strength of zerker builds isn’t to nerf zerker damage.
The best way is to increase the need for defense which can’t be mitigated by damage. The Krait tower living story was a good example. By instituting constant health degen, suddenly stats like healing power and vitality became more useful and desirable. If the degen scaled with armor, then toughness would be more useful too. Scale it with hp pool (i.e. it removes a % of your hp every tick, instead of a fixed amount) and vitality drops out of the equation. Lots of ways to tweak this.