Please, make the contents of the page occupy the whole page width, or at least make the code windows resizeable.
I don't think this would be a good upgrade to the site.
The key here,
Keep it simple.
If your code is too long it is already hard to read. Split your code on multiple lines and make it in a readable format. Don't forget we don't want to spend hours trying to figure out what you did.
Stack Overflow have the best formatting tools I've seen on any site and I can think of almost a 100 things I would change before that.
Also, don't you think these informations are relevant ?
I can't think of a way to make the code blocks resizable without killing the whole interface design.
I mean ... really ?