If you are opening up science to non-scientific theories then where do you draw the line? Who decides which theory is worthy of classroom analysis and which are not? Why your 'intelligent designer' and not the Flying Spaghetti Monster or any of the other creation theories out there? When it comes to testing, one intelligent designer is no more testable than another.
Excuse me, but ID is just as scientific as the evolutionary theory. Not to mention that it makes a lot more sense then the “Big bang” theory.