Min had a viewing that one people out of four in Tear is not going to survive TG.

Through the series, Jordan has peppered important locations with Portal Stones, and that includes right in the middle of the Seanchan front on Almoth, near Tear, near Cairhien, near Rhuidean.

There's also the fact the Ogier leaders are mostly at Shangtai, and a great deal of Waygates near stedding have not been permanently closed but are just guarded.

Overunning the Borderlands was just an appetizer, I think, and the evidence is that Lan who stands on the path to SG aside, the big battles there have happened off-screen or during acts 1-2.

The epilogue of TOM suggests very strongly the battle is about to begin in the center and south. The more scattered all around the map the Shadow attacks are, the more the Light has to make the hard choice between remaining united or spread out to face this, and that'd be the TW all over again. If the Light spreads out a lot, it will mobilize the channellers and cause the attrition of the army Rand needs to keep the Shadow busy at SG.

I'll be very suprised if Demandred don't strike at multiple targets all over the place, have shadowspawn armies assiege cities etc. To begin with, I'm pretty sure his strategy includes securing as many portal stones and Waygates as he can early in the game. His elite troops like channellers he may keep for higher profile battles and more strategic targets (and not only because the city and its people can become a food reserves for Trollocs), but the Shadow has a whole lot of Shadowspawn to spare, and the means to move them around en masse and fast enough... Trollocs kill population with great ease if powerful groups of channellers - or Rand - don't come to their rescue, each and every time an attack takes place somewhere. The population centres and civilians are extremely attractive targets, because not only the Light cares for those people and each big loss would contribute to lower morale and determination, but a great deal of the soldiers' families are in those cities under attack (how to remove Manetheren's army from the field? Strike at their defenseless civilians at home... the Shadow has used this strategy before) . That's an obvious "weak spot" to exploit.

So I'd be very surprised the South and center of the map will be spared by the Shadow. The more fronts the Shadow opens, the more it divides the Light. It would make very little sense to let Rand's forces transform themselves into a huge front south of the Borderlands, though it makes a great deal of sense to try to attract them there before striking all over the place... something Rand made redundant by assembling the main players and armies of the Light in one place. But the Shadow didn't know that, when the "phase one" of the LB started by overunning the Borderlands (which has apprarently succeeded, except in Shienar and Saldaea that still hold, or so it was suggested in TOM.)