Remember, Vince is extremely deliberate with details the show has and their impact.
There is a reason Hank is going to be extremely careful in how he investigates Walt. Remember Gus? Well,
George Merkert was the Assistant Special Agent in Charge of the DEA office in Albuquerque. Hank's boss, right? Remember why he lost his job, why Hank got his? George lost his job because of his close relationship with Gus.
Imagine what will happen to Hank if they find out not only is he CLOSE family with the cook of the most potent meth ever to hit the market, but that this same person has been actively paying for his health bills. To which Hank, given his position, never thought it was fishy, simply brought into Walt's gambling excuse.
If the DEA finds out about Hank's complicity with Walt, whether Hank ever knew anything or not, his career is over.
Hank needs to prove he is not with Walt by pretty much hand delivering the case to the DEA.
I imagine Hank is going to slowly creep out of that bathroom, smile awkwardly whilst biting his tongue harder than he ever had in his life, before he begins to intricately lay out a place for himself to investigate Walt.
I think yeah the storage unit will be the first big discovery, but I believe there is enough out there to uncover Walt. For example, once he starts looking into Madrigal again, how soon before he locates Lydia?