Honestly I don't feel the gated aspect is the issue, the issue is there are some things that have no point in being rerun after the first time through. Essentially any of the story mode trials (story primals and Westwind) have very few people returning to do them as they offer no reward to the members outside of story progression. This does get alleviated by having an active and helpful FC the first time through, or if you are an in demand class such as healer or tank.