The issue with the social lockout is that it drops those people from practicing from the actively sought practicing list, this is particularly hurtful for FC with not exact numbers- someone is bound to be left out (compounded when they actually want to use that knowledge). Forcing players to wait weeks till the next new content so they can do old content shows how bad the lockout system is. Besides its not like all these people who have trouble forming a static, for the number of reasons will actually decide that content is for them, being able to decide if it is for them is important- "wow this stuff is hard! Waiting till Echo baby" "lol this is awesome, thanks for the invite, that was so challengingly fun!". Carrying someone in the hardest content in the game is not really an issue for except the most generous and skilled groups, or groups selling runs. If selling runs hurts SE feels they can stop it without setting up social locks. If helping others is an issue then I don't know why this is called an MMO, should call it an MSO with really well made AI to abuse at your convenience, if you can meet their erroneous time schedules and social locked drama.
Loot lockouts do keep the loot 1 per week, or small other variations as suggested. People running through the content faster per week is not an issue, a few more people getting in earlier may happen but that should not be an issue*. Sure a few more people will not be left out but that - is the point -. As said before and said your self, most groups will not accept a dud player because it isn't that easy to drop people - at least until they are geared from the content themselves, which you showed issue to them helping others. Just make that gear synced down then, "but the point is for them to use the gear to make their own runs easier, not anyone elses- never share".
*I thought it was a joke before, but it seems like what a person said a few pages ago is actually closer to the truth- its the snowflake lock system, it seems the most popular issue against removing lockout but implementing loot lock is that they want systems in place to prevent others from joining in. I will never support the snowflake ideology. It is sad, imo, that the main proponent against removing the lockout but keeping a system that ensures SE has dev time for content is "I don't want other people to be able to do what I'm doing" - considering that every person that has a group is not available for another group, and that having static practice times across the globe of players is like trying to walk a cat. Why require the social stress for something that doesn't need to be, except to apparently make it so less people can do said content... I'm not impressed.
That the solution to the problem is to create another character shows how bad the system is. Also this shows the flaw to the system that a loot lock would -fix-. If you run with a set of mains and a set of alts, then the mains can focus roll on gear getting more of what they want concentrating the loot. Vs a loot lock system where it wouldn't matter, there is a set standard of speed. Seems to me loot locks are superior socially and mechanically.