Meh, nobody would sweat the 4th line forwards, they're a dime a dozen in this league, as are bottom pair defense. People are anyways pissed off about any of them being overpaid.It made enough sense for you to understand it was half of the defense. Kind of an irrelevant thing to even mention.
If we want to compare to forwards, it’s the equivalent of losing 2 middle-6 forwards, and 4 bottom-6 forwards. And Soucy & Cole may have been on the 3rd pairing, but they were still significant players. They ate a decent amount of minutes & it’s a lot easier to shelter a forward line than a defensive pair.
Defensive pairs aren't tough to shelter if you have a good top 4, as they can be minute munchers and take shifts with the bottom pair defensemen.