Balancing the Assassin for stacking means that he can only find proportionate strength in stacking. This is fine with everyone? I liked him as a real hero, not some support wuss.
Every other hero ability has a non-hero analogue, and common hero types do not stack. Why does the Assassin not have an Ambush ability called by a different name (just like all other main hero abilities) and stacking only with non-hero units? Assassination, stacks with Ambush but not Assassination? That seems like a bad name to me, but we can certainly do better.
I get it, Ambush is the only stacking ability in the game. It might be confusing if Ambush did not stack for heroes. Obviously, it's quite confusing that most main hero abilities don't stack and one does. I've played as much Warlords/DLR/Warbarons as most anyone here, and I'm quite confused by that inconsistency. So the "players might be confused by this ability behaving just like every other hero ability" argument seems very shaky to me.
Ideally, I guess we wait to see what comes forward in the new hero system. In the meantime I think it's important to keep these issues alive and in consideration for the next version. The wild inconsistencies between this hero and other heroes are problematic to my mind. If the stacking argument is valid, why Assassins and not Paladins, Dread Knights, etc.? Is this one hero to be balanced for stacking and useful only as support? A level 5 Assassin is kind of a piece of **** on his own, compared to a level 5 Paly or DK. Not the case a little while ago.