I think you're on the right track, but the onus is on buyers and sellers to simply refuse the services of realtors that charge a rate of anything higher than 2-3 percent, which is already astronomical. Anachronistic rates 4 and 5 percent stem from a by-gone era when home prices were $50,000 and $60,000. If you must use a realtor shop around, and do your homework. 

As for me, I would only ever sell my property independently rather than payout upwards of 10-15K for a weekend of work to a realtor. It's still shocking to me that realtors haven't gone the way of the dinosaurs. I suppose only once governments inevitably legislate more open and accessible information around buying and selling will that occur.