Well, there's been a whole bunch of debate about what relation the seals have with the taint. Maybe this should move to its own heading, maybe not. Anyhow, Fel said "clear the rubble, then rebuild." I think that it's obvious that he met the seals when he said this. Obviously the seals would have to be removed before the patch could be remade. If the old, decaying seals were used as part of the new patch, they would be a weak point and the sealing would once again be temporary. Also, we have the bubbles of evil that are being forced through the gaps by the DO. The only way to get rid of these bubbles is to seal away the DO, which has to be done by releasing him and having Rand defeat him. I think that Rand and Elayne will reseal the prison by using the two sa'angreal statues. This would give them sufficient power (power to challenge the creator, remember?) and by linking, Elayne could guide the weaves, since we know that she can make angreal and the like.