I say Funchess. I know he is a second round guy so maybe doesn't count as "surprise", but from a national perception point of view it seems a lot of people thought he would be a slow tight end with bad hands. If he can have a season similar to Kelvin's rookie season then I'd say that would be a pleasant surprise.
I don't draw the line in making fun of anything, because if I do, then I have to keep making concessions on what is and isn't acceptable to joke about. So while I understand some people will get upset, I simply can't allow myself to be drawn into that PC battle. Some of the most horrible things in the world give you the best material.
What year? I've been a season ticket holder for a long time through some really shitty teams and Oracle has always been loud. Couple small stretches in the late 90's and early 2000's was about as weak as it got, and even then the fans were pretty decent.