ahh I misread that. you are talking about the small party limit?
I believe he is talking about the fact that level fifties can only run one operation per week due to the lockout. If you have twelve members that are level fifty and only eight of them can run per week, it prevents the other four from running with the rest of the guild.
I personally think it's not an issue right now anyways; the lockout is meant to prevent people from getting BIS-gear in a couple of days. The game started less than a week ago, I think that people just need to be patient.