Did flex last night for the first time with a guild that has killed only the first boss on Flex. The group was mainly a very low end raid guild and some of their friends, me, the main tank from my guild and another dps later on. Well it was a nightmare after the first loot pinata. I'm not spectacular with healing on my priest, but I can push buttons well enough. 2nd boss went so poorly because the healers couldn't keep up that I had to switch to my shaman so we could get past it. After I carried the other 3 healers on my little goblin back, I proceeded to carry them on the 3rd boss.
Flex difficulty will be tough for the "average" player of WoW - typically with LFR you can coast by (especially on Tues/Wed when raiders are capping valor) because mechanics are toned down so much, but I think flex will present a lot of problems.
Either way, I'm always up for cross-realm flex if anyone needs a shammy healer! Mallika#1872 - I am Mallika on Drenden if you need to see gear/progress.