I agree with most of what has already been stated. Some people need a swift kick to the head when trying to lug some of their luggage in to the cabin. I often look at morons in disgust with what they bring on board. No respect for anyone else!
I think it's unfair to pick on 'suitettes' because 'suits' are just as bad, often with laptop bag, roller-bag and suit-bag.
My rule is if I'm not gonna use it on board, which is 99% of the time on Domestic flights, then it gets checked in. Other people need to follow this rule as well I reckon.
I think the easiest rule the airlines can enforce, without having a frame, is to simply only allow 1 piece of hand lugguage per person. Surely that would solve half the problem. Often it's not the size, it's the qantity. Parents travelling with babies are an exception of course, or those with special needs..