I don't think there is any doubt that dream refers to the Forsaken. What would a bunch of towers collapsing, and one almost collapsing all of the way, then recovering to be the tallest of them all have to do with a bunch of fortresses way far away in the Seanchen continent? Those happen to just be fortresses, and I do not think are metaphors for anything.

Those 13 black towers are definitely metaphors for the Forsaken.

The bigger question is which of the remaining Forsaken is represented by the one that almost collapsed but grew tallest of all. The obvious answer is Ishy/Moridin, but did he really fall? He "died" but the DO brought him back and he was still above everyone else. I am leaning towards Lanfear. She has fallen greatly and is basically a slave to Moridin now. Maybe she will come back as the strongest somehow.