a. Moiraine is capable of communicating the idea of an apology - wrt Thom, iirc in Book Three, or maybe the beginning of Book 4. While she may not actually say "Thank you", I am fairly certain she'll feel the debt. (Feeling the debt and hating it is why the younger three women - who were not Aes Sedai at the time, or suffering from the effects of long-term imprisonment, or from a different culture entirely which sees debts in a different way, or Tylin-the-sexy-rapist - behaved so damn badly to begin with.)

b. Mat is older now, and has suffered his own losses and gained his own strengths. If Moiraine does not say "Thank you", he will still have done what he did, and he will be okay.

c. I'm sure Moiraine will have experienced things - but unless they're soul-deep traumas, she will not be a drastically different woman from them, I would say.. She is much older than she looked when we last saw her, remember, and by that time one's character is pretty set, continuing along set paths. Maybe she'll be and look a bit older? It is quite hard to say.

And lastly, Sanderson tends to write rather differently from Jordan. He's doing his best to stay true to the spirit of the original texts, but I think it's unlikely that Moiraine will be egregiously intolerable.