Opt-in RBF fixes zero-fee transactions.
This what you're talking about?
https://en.bitcoin.it/wiki/Transaction_replacementTL;DR: the problem with beetcoin is not that the fees are high, but that you don't know if you have enough money with you to be able to get off the bus, because, unlike a bus, beetcoin doesn't ask for your fare to get on. It lets you on, but if you don't have enough change on you? Have fun riding the bus. For the rest of your life

That much is true.