Both are possible - that the seals have prevented any widening, or not. Some see the seals has seven additional protective layers put between the pattern and the DO, some think the DO could still work on enlarging the Bore beneath the sealing, that the sealing isn't perfect enough to have prevented this.

The way Rand speaks, and he's no doubt relying on LTT's knowledge, he seems to expect underneath the sealing things have gotten worse. Whether this is because the Bore has kept thinning the outer layer of the Pattern over time or because the AS in the AOL could do something to hold the Pattern together they no longer could do now and so the same effect of the DO will be more dire now, it's hard to say. We'll have to wait on the POV of Rand or a Forsaken to know for sure what's up with the Bore.

There's a theory that the Bore couldn't enlarge while the seven seals were in place, but that it resumed widening since the first seal broke, and that this has accelerated with each additional seal breaking. So now the situation would be somewhat worse that it stood at the end of the War of Shadow when the Sealing was put in place.