I can understand pro and con of having content locked so that players would develop their skills together with their group of static and no any helping hands from outside.
However, I think that this is starting to get boring, as you are semi-forced to play the only available end-game content with the same old face over and over. You have many more friends than that but the content you could play with them are pure worthless easy-content that not actually worth much to do.
Since there are many pro and con for having end-game content as locked and not locked. Why not release both type of end-game content? One that is locked and one that is not locked either on the same major patch or different major patch such as 2.2 (lock one), 2.3 (not lock one), 2.4 (lock one), 2.5 (not lock one).
The current idea of SE design is 2.2 (lock + hardcore), 2.3 (not lock + casual), 2.4 (lock hardcore), 2.5 (not lock + casual). Which I believe that there aren't any "not lock + hardcore" at all. This is the missing element!
Will they ever bring any End-game content that isn't locked?
(Please do not speak on Ramuh, most end-game players not interest to it. We won it once and then never touch it again or barely. Level 100 will not bring much intensive play to us when we already have all 110s. )
I remember that in 1.0 days, AV and CC were actually pretty good end-game raid design and they are not locked. Could they do implement something like that again so that end-game players could overlap and play freely between cross-static? Of course, the reward should be on pair with the locked one if they were to be released after, else, it is going to be just vanity.
To summarize this up:
I think we should have another kind of content that is equally hard to Coil, but "not lock". So that end-game players can enjoy free party system with challenge and worthwhile content.