Arguements like this have been coming ever since DL took Ravager from Barbs and reduced the reliance on rage/con, and on the face of it, a call to nerf may appear reasonable, superficially at least.
However there are a number of aspects that help to balance Visage in context...
It is a capstone, so precludes any multiclassing. In today's meta, that can prove quite a limitation.
It's capstone in an otherwise pretty underwhelming tree, so you're spending 41 points that could be spent more effectively elsewhere.
It's application is pretty limited. It doesn't work on undead or constructs or slimes, and that's a surprisingly significant proportion of mobs. Also completely redundant on red names, bosses, and higher reapers. Largely useless in most raids too, I've found.
These limitations combined, make Visage a consideration rather than a no brainer choice for build. Nerfing it will likely, and certainly in my barbs case, weight matters heavily towards the more DPS oriented multi class 41 vistani type builds.
Do I want to give it up for 40 more MP, haste boost and attack speed?
Maybe.
But nerf it, and that becomes an easy decision.
I'm not sure that represents balance. It certainly takes us down a more standardised approach by removing it as a desirable option.
I'm not denying that DL is OP. Most latest shinies are. But I'm not convinced Visage is the main culprit here.
Nor is even DL close to imbalanced when compared to the abomination that is apparent in certain zero risk ranged builds right now.