I'd have to think that if Goff is traded, then even his supporters will move on from that. He's our QB right now, so we support him. But a trade of Goff is understandable. This isn't a Dickerson type of trade. I think we should keep Goff -- but i understand why McVay would want to find someone else. We move on from Gurley/Peters/Cooks/etc. and nobody pined for them constantly. We'll move on from Goff, if traded, as well.
It depends in large part how his replacement does and how Goff does with his new team. And it's different at QB because that position is harder to fill than any other, hence the huge salaries. Losing Gurley sucked, but we had already lost him in a sense when his knee issues flared up and made him less effective. Cooks is one concussion away from a career ender. Peters was a mixed bag in his time here, showing some great assets but also some huge liabilities - and in his case, the guy that effectively replaced him (Ramsey) was so obviously superior that Peters was not missed.
Goff on the other hand is a relatively young QB, a pocket passer who is still not entered his prime. For moving him to look good, either Goff needs to totally collapse with his new team or his replacement has to be obviously superior. The only obviously superior option that we have any sort of chance of acquiring is Watson, and that's a long shot and a very heavy cost.
If the new guy doesn't provide an instant, obvious upgrade over Goff over a whole season, people are going to start questioning the move. If Goff lights it up with another team, people are going to start wondering why McVay couldn't have gotten that production here without going through all the offseason drama and dead cap. If both of those things happen ... look out.
We've seen this movie before in Ramville, and I have a bad feeling we are walking right down that same road again.