I'm not sure of how much use this would be on other SEs, but on CodeGolf.SE, we use Stack Snippets more often to actually provide useful functionality, than to demo some code of interest.
In that case, no one wants to look at that huge wall of code, all you want is the snippet. So what I tend to do is run the code through external minifiers, so all the line breaks go. Since I've got to use separate HTML, CSS and JS minifiers, that's quite annoying.
It would be nice if there was a "Minify" button next to the "Tidy" button. It doesn't even have to shorten variable names and stuff, just get rid of unnecessary whitespace - basically the exact inverse to "Tidy".
(Yes, I am aware that snippets can be hidden by default, but once you expand it, you still have to scroll past a wall of code to get to the actual snippet.)
Edit: Being able to hide/expand the code and the button/snippet individually, would also solve the problem.