I'm curious to see how it all plays out in Toronto and Columbus. Toronto is screwed unless they can dump either Nylander or Marleau and Marleau has a full NMC. I can't see either Matthews or Marner not asking for 11-12M+/year. Marner is setting scoring records for a player starting their career with Toronto, and Matthews is almost to 100 goals in his first 3 seasons. So they are pretty well screwed.
And then there's Columbus who knows they are going to lose at least Bobrovsky and maybe Panarin to Free Agency and are betting that they can make a run to win a Cup, regardless of what it means to their future chances of winning. Would having Werenski getting offer sheeted give them the draft picks to get them back in the game quicker than if they still had Werenski? Maybe...maybe not. You'd have to have confidence that you can draft well, in 2020, if you're Columbus. If I'm Detroit, I definitely take the gamble because you won't lose any picks, this year, and you might still be able to get enough picks in 2020 to make it all come out in the wash, but having a legitimate top pair d-man on your roster with good NHL experience and only 20 years old (current age).
I think if Detroit were to offer sheet anyone, Werenski comes in at a decent price for the long-term security of our back-line.
Edit: If we offer Werenski between the $6,088,981 to $8,118,641 price, we would only lose a 1st, 2nd, and 3rd rounder.