I don't think bzd survives past year 4 if he doesn't get us off the bubble regardless of whether Wellman is "happy" with that level of success or not (doubt he is). If Bzd keeps us at 18-20 wins he will not generate enough fan/alumni/donor support to save his job. Sendek survived so long at NC State because he followed Les Robinson and he had fan support for a good long while. Until they got used to winning more games than they lost (without committing recruiting violations) and asked for more. Bzd is not going to have that luxury.
We need to make the NCAAs relatively easily in Year 4 and if not get to the Sweet 16 that year, then def. the next (either that or win 3/4 of our games in the ACC). I really do think he's going to have to get to about 42-44 wins in Years 3 and 4, with at least 18 of those coming next year, to generate the backing he needs in the expensive seats.
So I really don't think your fears are warranted. If it was Shaka Smart everyone would take 17 wins for two years with a shit eating grin, but Bzd is certainly not going to be afforded that luxury. Remember, everyone liked being in the company of Skip. 5 minutes of time carried a lot of people a long way with him. There are only a handful of coaches charming enough to get away with putting your worst free throw shooter on the line to take technical free throws, and Skip was one of them.
It will be villagers at the gates in Transylvania if Bzd makes that kind of mistake. He's on a short rope and he knows it. Sucky way to have to work but he brought it on himself as much as Wellman put him there so I don't feel too sympathetic.