I'm also tired of the solution to just use the phone number and carrier name with your email instead. Why can't people (and Apple) understand I can't force OTHER people to NOT send me MMS! If you have, say, roughly 25 people you stay in contact with via text messaging, is it reasonable to have to explain to EACH person why they need to send you email rather than text? Even though they may not understand why EVERYONE else they text doesn't need to make this request?
I blocked MMS on my account, so you CAN force people not send you pictures.