[Snake]

A few things being removed from main class only will certainly bring back Void Assassin, in my opinion. But many might just disagree. My idea about what should or not be locked away in VA are:

Voidveil shouldn't be main class only. Voidveil's damage reduction effects should be halved if sub-classed.
Detogate should be main class only.
Black Bolt should be main class only.
Dagger Dance shouldn't be main class only. (And I say Dagger Dance because it only really interests VA, in the end of all.)

Void Assassin, as a class, doesn't offer much or enough to have the MC treatment. If only it had a hundred more skills like Spellthief or Demon Hunter does, it would warrant it, because you would have more options to pick, even if that is sub-class. But sadly, that's not the case, for a class with only like ten skills added to it, and one being a passive that works more like an innate.