I think anyone claiming that Yzerman is going to fleece JBB because of his mentor status, forgets that Yzerman negotiated the deal with Holland that sent Kyle Quincey to Detroit for what turned out to be Vasy. It's been supported on numerous occasions that JBB has been in the ear of Yzerman throughout his tenure here, if not in the room for the conference calls and trades.
On the part of Yzerman knowing the roster front and back, that much is true, but I don't see that as a precursor for some deviant acts to follow this summer. If anything it's a basis for dialogue to help both teams out, it could be a very good thing to have occurred.
There's also the ole Yzerman Pump N' Dump. I think JBB's going to understand how Yzerman likes to sell players according to their perceived value (Conacher, Namestnikov) rather than their actual value.
I do see these two working together in deals. Despite being in the same division, Detroit is several years away from being a rival of ours. We look almost ideal as trading partners, and I think these two respect each other enough to make deals that will benefit both teams. Wouldn't be shocking at all if Callahan winds up in Detroit next year, for instance, and Yzerman knows our prospect pool enough to know a fair price, which fair price he no doubt shared with JBB, last year, when they were trying to acquire Karlsson.
The scary thing IS if Yzerman takes a significant portion of the team with him--mainly Murray. We know JBB played a part in the day to day duties, but Yzerman's main strength was putting the right people in the right jobs, and, as SAI said, getting out of their way. We don't know yet if JBB has that same talent.