Technique bans tend to be unenforceable.
But there's a deeper reason that I don't like them. I never want to be in a situation where we go into a brawl match, but anything I might happen to do within it would disqualify me. I mean, I'm here to play the game, not play the game while being consciously of how my actions might violate some tangential set of human-applied rules. In particular, I'd like that no accident with my controller should be able to disqualify me. I'd rather ban the stage than have the risk of violating constraints which aren't actually a part of the game.
Outright stalling, as far as I know, can only be done by a handful of situations, and requires a conscious effort to pull off (it must be intentional), for a long period of time. Chaingrabs, on the other hand, are a natural part of fighting; telling a D3 that he must input a dash in-between grabs, for example, puts a real constraint on the types of mistakes one is allowed to make while playing, which I think is dumb.
SO yeah, if D3's CG is truly degenerate on GHZ, then I'd rather see the stage go than an attempt to ban the technique.
Even if you were going to try to ban the tech -- what exactly would you do? No chaingrabbing, or just no chaingrabbing off the side? What exactly constitutes a chaingrab, and which inputs are prevented to stop it? Would such a rule prevent legitimate, non-banworthy tactics from being used as well? It's generally a very tricky matter.