I think Gaudreau is worth Pasta, especially to Boston with his history there and considering the contract situation going on with the B's. And if I put my feelings as a fan for Gaudreau aside, I prefer Pasta who is someone I've followed closely since being drafted. Not by a lot, but enough that I would do it because it fills a position of need and we wouldn't lose any offence.
So do you just not like Gaudreau or something? I would not trade Gaudreau for Pasta as imo Gaudreau is an elite talent and drives his entire line. Even in an off-year with no training camp, no time to build chemistry or learn the system, missing games, playing injured, and being the most focused guy on our team by opponents, he still put up an amazing PPG and the most points out of our entire team. Just look at the monthly splits; after the team learned the system and gained chemistry in the first few months, he was on fire nearly every game (despite playing injured in at least 10 of those). He's not even a no-show in the playoffs like some would have you believe.
Pasta is not a bystander but not the main driver on his line either (I don't think that line has a main driver). He's impressed in every season he's played in, despite playing fourth/third line minutes for his first two seasons. However, with the quality of his linemates considered and the kind of chemistry he has with them, I feel like his value comes a little more back down to earth. I could definitely see him reaching Gaudreau's level but then again, this kind of trade is banking on potential.
If it doesn't work out, our offence loses its most dynamic player and loses skill. If it does, we might get a marginally better player who would make our offence only slightly better. The risk isn't worth the reward.