This whole rebuild thing keeps pulling me in different directions, but as a 44 year leafs fan (ugh), if done right, a rebuild doesn't have to be a negative thing. If (and a big if) they sold JD, Osuna, Stroman, and the expiring contracts, you would hopefully be looking at multiple blue chip, top of the line prospect/3-6 talents suddenly added to the MLB/AAA teams. You would have the "faces" of Tulo, Travis, Alford, Sanchez to appease the casuals along with any new talent. And the best bit is, that just down the Qew you would have the blue chippers getting primed for the big club. To use the leafs reference again, I would bet that the Marlies popularity is at an all time high right now with the harcores and even some casual fans, because of proximity and talent.
And you still have Vladdy and Bo coming!
I guess, in a perfect scenario, the MLB team would suffer limited down time before they were competitive again. But then again, you could do a quick turnaround with some luck and the current roster...