My solution, get both. Then, shoot weddings exclusively with the 17mm tilt shift. Your unique perspective will set you apart in the field.
Likewise architecture: only 70-200. Tell your clients their interiors are the problem not your shooting technique. If they can't convey the room in a 2x2ft area of that room, you are not at fault.
You will be called a visionary, an artist unwilling to compromise to conformity.