There is a HUGE HUGE difference between an openraid pug and a /2 pug. I run an openraid pug every week, and it is very fast and successful.. because at the start of a new boss, each and every players already knows what I am going to say. They know all the major mechanisms from icey veins and only need to know orb order and stuff like that.
My actual biggest fear is that everyone starts knowing about openraid, and it ends up just being an ingame queueing tool. I love flex because you can´t ignore mechanisms and you have some personal accountability.. There needs to be a barrier to entry for LFR players... they shouldn´t be able to just queue for it like LFR.