I would want to see more detailed character models before this happens so we can see our fancy clothing in all it's glory. Not super detailed mind, just something that doesn't look like the little wooden boy from the Tick cartoon... I do like top hats though, and goggles. =D
Three words come to one's mind after reading some of the Team Fortress 2 references that have been mentioned in this thread.
"LOL U MAD"
If any such thing happens I am likely to somehow crawl through the series of tubes, as it were, and engage in an act of homicide.
That said, I am all for the idea of hats. A top-hat would be an excellent addition, as long as you would be able to obtain a cane.