There are a few things related to coaching that would be worst-case scenarios, namely the Jets as a whole not responding to Arniel's coaching style or Arniel trying and failing to implement big play style or identity changes. Both seem unlikely, though, as he was part of helping Bowness mold the Jets into the defence-focused and tight team they are today.
The Winnipeg Jets have also hired assistant coaches Davis Payne and Dean Chynoweth. Davis Payne will be responsible for redesigning the special teams unit, specifically the power play which was ranked 22nd in the league last year.
In a worst case scenario event, the Jets players do not respond well to the new structure implemented by Payne, allowing the Jets power-play to sink further down the standings.
Although these are highly unlikely situations, theres always the possibility of players not responding well to new coaching staff. Scott Arniel seems to be embracing his new role by developing close offseason connections with some of his key players like Cole Pefetti. Will the Jets respond well to the new coaches this year? Only time will tell.