I'm not sure if it's been brought up in one of the twenty five pages here, but I assumed that the change in Taim's followers and the Aes Sedai was a power of the dreamspike. Graendal did say that it was a very powerful weapon, and turning peoples' minds would fit in that category. So far all we've really seen it do is prevent people from Traveling, but I think that it can be used to enter someone's dreams. I vaguely remember Lanfear implying that she could break through a warded dream to make Rand love her. I know she said she could break through, I'm wondering if that's why it's called a dreamSPIKE. It can spike through a warded dream and give you access to their thoughts etc. Then you could presumably control them and turn them into the husks of people that they appear as. It would also clean up the issue of whether men can link with Myyrdraal. Just my thoughts on the subject.

I think it's called a dreamspike because it's

a long, spikelike piece of metal

Incidentally, that was the closest thing to a cringeworthy sentence in TOM. Spikelike.

 

As for giving it powers beyond affecting a region in TAR, I doubt it. Tarna was 13x13ed.