Suggestions and ideas for increasing interest in previous PvP content

[Eorzean_username]

The Grand Company lock is the biggest issue.

GC restrictions hamper the PvP base, but it's not the only issue and I think players fixate on it slightly too much. Consider:
Edited with Zojha's correction about Feast

• Feast 8v8, no GC restrictions (but role restrictions, which may be equally problematic), 20-30+ minute queues (for a 5-8 minute match) during Feast meta. Now roughly ∞ queue times with Shatter released.
• Feast 4v4, no GC restrictions (but role restrictions, which may be equally problematic), 15-20+ minute queues (for a 3-5 minute match) during Feast meta by the time I arrived late in the season. Now roughly ∞ queue times with Shatter released.
• Secure, Slaughter, Seize: Massively higher queue times than Shatter (trending to ∞ also) despite being the same content and having the same GC restrictions.
• I deliberately switched to a minority GC, cutting my typical queue times down by 50-75% of what I had to sit through as Aether Flames. However, I still encounter intermittent dead periods where the queue will tick up 40-45 minutes or longer. After I load into the match, if I ask around others experienced the same thing (so it's probably not some mysterious queue bug, it's just not enough players queuing at all during some play windows).
• JP datacenters have stable queues despite GC restrictions (My understanding is that JP dislikes GC restrictions for reasons of inconvenience, but not because GCs are stopping them from playing)

I don't think that removing GC restrictions will resolve issues like high turnover rate for previous content and a relatively small NA/EU PvP population. It's definitely one of several issues surrounding PvP that should be iterated and improved just due to community mandate (if nothing else), but I don't think GCs are the only issue and if other problems aren't also resolved, the result of GC dissolution might be surprisingly disappointing.

Something else to compare is PvE content with drastically high or effectively ∞ queue times: L50 EX Trials, Coils, and Savage Raid Finder. Similar to PvP, these:

• Are not a guaranteed victory (baseline or when sync'd down with strangers)
• Require coordination and communication (baseline or when sync'd down)
• Offer minor or zero incentive for using the Duty Finder to do it

On the other hand, even relatively small bribes like 120 Poetics is enough to keep MSQ Roulette (of all things) popping fast and consistently all day long. Many players are not thrilled with it, but they definitely do it.