I'd have to side with Fish, but it is another of those matches that Raonic can most definitely challenge for.
Fish should protect his service games, as long as his serve doesn't drop off. He might struggle to break, like the others, but if he can carry his tiebreak form over from 2010 he is certainly capable of making the right moves when it ultimately counts.
The question, for me, is whether Raonic can continue to make the play when he is asked to do so. For the last 2 weeks he has come up with the goods (except in that exhibition against Karlovic), but here he is playing for another final, in a larger event, as a new member of the top 50, against a very experienced, established player with home support. That is quite a lot for him to turn over in his mind over the next 24 hours.
He isn't going to freeze, but it might be enough to sew a seed of doubt in his mind if his game isn't firing on all cylinders.
You also have to question whether Fish is fully fit, and able to bring the sort of tennis to the court that he was playing in his resurgence last year. If he is, it should be too good.