First, I agree that Mat feels a bit off, but I think that people are being too hard on Sanderson here and not thinking hard enough about Mat's situation.

He is currently in a sort of shell-shock - his entire world has changed.

He's now married to a strange and frustrating woman from across the world. And he's fallen in love with her. These two are enough to throw him completely off. But, she's also heir to an empire and his marraige makes him a noble of all things (thankfully he doesn't yet realize that Tuon is now Empress).

Mat is reacting to his new place in the world which explains much of what's going on. He's supposed to feel off because his entire world has changed.

So, I'm still confident that Sanderson will do Mat good in ToM.


Of course, I also think that Mat didn't really need to be in TGS at all and that the Hinderstrap chapter in particular was a complete waste of space.