Fascinating stuff.
Ramsey is not as devious a plotter as Roose, and to a considerable extent has been lucky. I think he is going to roll the dice again, using Reek/Theon.
If those northern lords who are with him can be convinced that Ramsay is marrying the real Arya Stark, they will throw their support behind Ramsay willingly. Especially against a southerner like Stannis.
So Theon must be seen to be uncoerced, and given a chance to recognize the "real" Arya Stark. To that end Ramsay will have Theon cleaned up and rehabilitated as much as possible. (Uncoerced is a relative term of course, since Theon's mind is broken.)
When Theon and Arya/Jeyne Poole meet, the northern lords will be watching closely. Ramsay knows that the results of torture are uncertain, but he likes a good gamble. And Theon certainly has shown that he's willing to do anything (anything!) to survive, so its not that bad a bet.
So can we actually expect one last spark of nobility from Theon, and the actual truth, before he dies?