It's odd, as much as I've been wanting to see this fight, I know just as well how it will end, Ward by late stoppage and if the fight ever happens you can mark my words here. Could be wrong, but I doubt it. I like Dirrell, I really do, but he doesn't have the ring I.Q, or the focus to beat Ward. It's odd that even still Ward is underrated in certain departments. His speed and strength or underrated, as well as his outside game.
Ward is an absolute master at controlling distance and anticipating, and equally as good at countering what he's anticipating. Against Dawson, he lead with punches to read how quickly Dawson could/would react and to see what he was throwing, and as soon as Ward got a feel for what Dawson was doing he turned it up a gear and that was all she wrote. Dirrell, who I feel is a bit more talented then Dawson, would have the same issues.
And while Dirrell has fast hands, Ward is just too good defensively to allow himself to be touched and he would be timing Dirrell. I'd also say Ward that while he is just a touch slower then Dirrell, is still the better technician and has much better footwork, which is exactly why I think Ward wins. Ward's excellent jab and footwork would set up good shots on Dirrell who is usually hard to tie down so to speak.
I would expect Dirrell's herky jerkiness to make things awklward in the first 4 rounds, but Ward would start depositing that stiff left jab to the solar plexus, and would poke a whole in Dirrell's gas tank, and by the 10th round Ward would be in complete control and Dirrell would be spent, and in the 11th Ward stops a spent Dirrell who is languishing on the ropes.
Dirrell beats every other SMW, IMO though.