While I would not object to what you propose, I doubt it would change behavior significantly. People who are inclined to think about the interest and overall costs are already easily able to access that information. People who aren't inclined will see 3 additional pages among the 120 pages they see during closing or 30 they see during mortgage application/qualification process.

People who can't (or don't want to) math aren't likely to suddenly do so because of an additional disclosure.