It wouldn't surprise me if Detroit shopped Kubalik in the summer, there was no market for him, and Yzerman said Dorion had to take him.
He's not a 2.5M player in the current anarchy that is today's salary cap. Sens were probably fine taking him because:
1) They didn't have a choice, they needed to work with Detroit to get a return on Debrincat.
2) They may have thought they were out on Tarasenko. So they needed scoring depth to replace Debrincat.
3) They didn't have a choice.
Doesn't mean he is a bad player, but people think back to him scoring 30 goals 5 years ago. If he was a UFA this offseason, he likely would have signed somewhere for 1M-1.5M. He's a 3rd line goal scorer/PP guy who scored goals playing minutes on rebuilding teams against easier competition. Which doesn't mean he isn't a good or useful player, but a lot of people took the Bruce Garrioch puff pieces to heart and seemed to expect a top 6 forward.
There is a reason Chicago didn't qualify him, and he only got 2.5M x 2 1 year removed from a 30 goal season. We're now a few more years removed from that season, the cap hasn't gone up much, and he hasn't done anything to improve his value. He would clear waivers right now, and it's not because he is a bad player, it's just bad timing with the (near) flat cap and how his contract relates to that.