When Flex was first announced, I remember there was a lot of excitement from guilds who were stuck somewhere between LFR and Normal, frequently plagued with attendance and real life issues, who thought this was the answer to their prayers. Then the idea that it wouldn't scale under 10 burned some people's biscuits but many of them were still excited.
So if you were apart of one of those guilds, was Flex the answer you were looking for? Personally its just a way to Pug something for a piece of gear I might be missing... (Haromms Tailsman.) My old guild who has sadly begun to see its last members log in less and less were no longer running it within 2 months or so of Wing 4 being released.
Once again this isn't really about individual players as it was guilds who were thinking it was the answer to their problems, and how successful it was in that manner.