You may be overthinking it. The darkly hilarious tragedy about Hank is that he is an otherwise competent cop who really is that clueless about Walt. He made up his mind about the guy a long time ago and it's going to take the equivalent of a frying pan to the face to get him to view Walt in another light.
They've been dumping fairly obvious clues on Hank's head since the pilot (where the equipment was stolen from Walt's chem lab), and Hank has yet to put 2 and 2 together, so it'll probably take a major singular event to get through to him rather than a steady accumulation of clues which he tends to just brush off. The irony will be that the major drug chemist will have been right under his nose the whole time, with several clues pointed directly at him, and Hank won't have gotten it until something big and potentially tragic happens.
Hank has noticed something different about Walt, but the only thing he went as far as to suspect was Walt having an affair, and when Marie switched that around it basically reset Hank's suspicions about Walt and he viewed him as even more of a sad sap.