That would have been the best way. I think I even mentioned somewhere before that this would have been an easy and obvious thing to do. Arguably even easier than what he did in a way since Rand could have been able to see Graendals death with his own eyes that way.

But while RJ says this might be done(blocking gateways), I don't think Rand knows how. I wonder if that means LTT does not know either. I would have expected that he would but the fact that this is never considered might imply he does not. Unless ofcourse this is one of those facts Rand has yet to learn.

I wonder if this might come into play in the next book. Maybe the new Rand/LTT combo coming down from Dragonmount will teach the Asha'man to block traveling. That might help blunt the Seanchan advantage of getting traveling from Elaida.