Although no one has shown it so far in the books, there are ways to interfere with the making of a gateway - and ways to defend against interference - so the battle would take place on many levels.

First off, what Rand did was interfere with the closing of a Gateway. The same may prevent a gateway from opening (though Asmodean doesn't phrase it that way), but that weave doesn't interfere with the making of a Gateway, as RJ said. More importantly, RJ also made it clear we've not seen such weaves in the books, and QotW was well after tFoH.

Now, you could state that every front line was manned by channeler's 24x7 and they merely sliced the weaves of any forming gateway, but that doesn't make sense. We're talking of hundreds of mile long fronts here. And what about behind the front? Are you seriously claiming channelers could stand vigil over the entire territory they wanted to hold?

That makes no sense, and stretches possibility. What makes sense is wards, made using sa'angreal to cover the region to be held.