These days I use mathcad for homework. As it is, I have to put each problem in it's own sheet to avoid accidently reusing a variable from a previous problem. Then I export each to it's own pdf and glue them together. I wish there were a 'clear' function like there is in matlab that would wipe out all previously user-defined variables.
I'd also like to see a Vector graphics editor (like xfig) built in so we can draw on our sheets. I've always thought of mathcad as a piece of paper with a built in graphing calculator. But what kind of paper is it that you can't draw on? Using images for this is clumsy. And bitmap editors like windows paint are too painful to edit the results in. It needs to be a vector graphics editor. Such a thing is almost trivial to code.