I felt Martin went well overboard with this. I didn't like "Cat o' the Canals" in Feast, as Arya has always held true to her self (and people she needs to kill) and it's ramped up presence in Dance was largely unwelcome by me.
It worked sooooo well for the Reek to Theon shift, but I found it distracting and useless with Asha, Victarion, Barristan, etc. The ones that shifted for plot points rather than the person changing were, for me, the worst. It seemed especially egregious with Asha, who was always Asha.
In fact, the over- and unnecessary use of it with other characters lessened the impact of what he did with Theon.
What does everybody else think of this? They mostly gave me the sense that Martin was bored and coming up with them was a nice little distraction, but I'm willing to be swayed to liking them.