I would like to have the ability to create a vertical splitter that enables divs/panels on either side of it to be dynamically resized horizontally. An example of this behavior can be seen at this site from IBM. It's fairly trivial to implement in JavaScript, which of course I can't use on Wikidot. Here are a few example implementations (none of which are my own):
Some other examples of sites that implement this behavior to provide inspiration:
This format is far more flexible than most "responsive design" techniques since it lets the user adjust the ratio of menu to content to suit their needs rather than having the site guess at what the best size would be given the user's screen width.