Obviously anything less than the playoffs after finishing last in the league would be unthinkable.
Given the context of a likely 40+ goal Skinner, 90+ point Jack, and 10 game win streak, yes, it would be unthinkable, as we'd be one of two teams to ever miss with a 10 game win streak IIRC. The other being Columbus who put it together in March after being like the worst team in the league besides the tank Sabres for the first 5 months of the season.
And it would cement the Sabres as the only team to finish in last in the last 5 seasons to not make the playoffs the next year, unable to do what other teams did THREE times in that span. While several other bottom-of-conference-but-not-quite-last-place-teams joined those other last place teams in making the playoffs, while we sit aside as the special-bad team that can't even make it with the above things going right, because of a hole they felt like making and not fixing.
It would be f***ing ridiculous to waste another year of Jack's prime with all of that going right, yes.