People have been debating that Verin was BA for years now, where you've been Bookstore guy? There was a line somewhere in the books about her making a "mistake 70 years ago" and that she wasn't going to let it go to waste or something like that. So yes I think there is back up for Verin being a double agent, ever since she said those fateful words "Moriane Sent me, Lord Agelmar"
Once again, I'm not arguing that there was nothing saying she wasn't BA. I'm pretty sure I've said that isn't my issue several times. I'm saying that, in my opinion, the manner and timing of the reveal were beyond convenient, and it served to cheapen the 2nd part of the reveal--that she was really a good gal. My last 4 posts have talked about timing and coincidence, not how surprised I was. Her being BA wasn't really surprising (and if anyone missed the "Moraine sent me" part, they surely didn't miss Moraine telling Rand not to trust Verin). It was more of a "Well crud, I was hoping for a cooler reveal. Oh well, at least now she can be evil...oh, never mind, now she's a double agent on her deathbed. How perfectly convenient for Egwene." The two "reveals" put that closely together don't add together and make each other stronger. They make each other weaker. As I said before, I personally feel this was poorly handled.
Summary:
1) I wasn't surprised by Verin being BA. I wish she would have had a big powerful reveal earlier and been in danger from the main characters.
2) I was surprised that she was a double-agent, but being so close to the focal reveal to Egwene that she was BA weakened the double-agent reveal and made it less important than it should have been.
3) Hindsight is 20-20. People can look back and say that one theory was perfect (even though there were dozen of theories that were simultaneously proven false). We could have had a dozen final outcomes that fit the small bits and hints that were given.
4) The timing of the reveals were rushed and coincidental/overly convenient. It is borderline Deus Ex Machina.
5) I suppose I shouldn't be surprised that Verin turned out to be good. It helps further guarantee that the Light will win. It's like the Aes Sedai said, "What does it matter, we are going to win anyway right?"
6) This didn't ruin the book for me. While I'm not a fan of the series, this book was enjoyable overall (it wasn't TGH by any means, but still good).
I think we've beaten this dead horse enough. Like I said, I don't expect any fan of the series to agree with me.