If he and Iso Joe both leave, yeah, the Nets are going to be awful in 2016. In theory, they would have room to sign people for 2017, but if the goal is to sell the team, they may not care to add much payroll. The Nets have pretty much one avenue to improve, and that's to sign FAs, but while they might have more cap room (Johnson is off the books after this year, anyway, but I'm not sure how Deron would fit into their cap if they release him...I think there's some cap penalty still, no? Didn't we carry Rasheed's salary on our cap after he retired?), they won't have an insane amount given the contracts they just gave to Mr. Glass Lopez and Thad Young, and its not exactly a really attractive destination given the fact that they won't be very good and they have no new young talent coming in for a while b/c of the trades. I just don't see impactful FAs wanting to go there with a barren team (if the Nets even try to add payroll, which I suspect they won't, if the goal is to sell the team). At worst, I think this bodes great for us in 2016, and at best, I don't think it hurts us much in 2017 re: the picks, either.
Re: the Mavs, I don't see DWill getting them to the playoffs unless he finds a time machine. I do think it helps them not get a top 7 pick...as-in, I think it keeps them in the 7-12 range.