If 5.5 would have gotten Morrissey on a long-term deal, I would have pulled the trigger without blinking. The D corps is too worrisome for us to take any additional risks, which include letting Morrissey get closer to UFA, with arb rights and a big payday looming ahead.
Think of this: when Trouba, our #1D, is traded, who gets his money? I have a hunch that it is going to be a bottom pairing defenseman who people think is going to be able to fill Trouba's shoes. This is even after years of production that suggests nothing of the sort. It is because of this why I am pissed off: Trouba's money should be spent on actual core players, such as Morrissey, possibly Connor etc.
It is one thing if Morrissey did not want to sign long term (and given how underpaid some defensemen who did that are today, I can't blame him), but I highly doubt that a player is willing to give up so much security.
Morrissey at 5.5 is very much worth it. You can pay that without losing your sleep. There are Jets who are not worth their deals, and they should be the ones that are shed to make room for the contracts that are crucial with regards to our future.