The solution is definitely to make an easy but slightly limited editor. The advanced features can still be in there, but slightly hidden away and would rely on a lot of work in notepad.
However, I've worked so hard on Knytt Underground over the last two and a half years that I'm not sure I can manage to create an editor right now (I need a bit of rest first). If I could get help, it'd make it a lot easier. If Knytt Underground generates a nice profit, I could hire someone to help me out for a little while.