If the offer sheet was the problem, don't match it. Take whatever the compensation was going to be, and move on. If he had signed an offer sheet with Vancouver, ok, maybe he'd rather be somewhere else in that scenario. With Philly, he's just looking for the best contract he can get as a RFA. Especially before the new CBA.
Part of the reason the trade was shocking is from the other side. It's not just Subban and Montreal. At this time last year, who thought Weber wasn't going to be in Nashville forever? When Subban was going through his contract stuff, people questioned if he wanted to stay, or if Montreal truly wanted him. When Weber signed the offer sheet, I'm sure people asked the same questions.
That's how money works. Unless the player takes less, or the team just throws the bank at the player, there's always questions. If the player wants a ton, what about loyalty? If the team is being stingy with a great player, what about taking care of your employee?
I'm guessing Nashville thought, well, we've been to the 2nd round a few times, but haven't gotten past the 2nd round yet. Whatever the exact player ranking, it's not like we're trading Weber for just some guy. We have a coach that's more go-go-go. Our fans are expecting more. We're even getting younger in the deal. Let's give it a shot.