I'd like to propose that whatever Tomestones are the highest tier in any period of the game's life to be job-specific acquisition. It seems silly to 'earn' best-in-slot gear for a role that you never play.
The main things I've noticed about the game not quite filling it's potential to me all seem to revolve around the same thing. People being on jobs they have no idea how to play, but they have 'best-in-slot' gear; people logging in on Mondays getting their lock-out caps and disappearing til the next Monday, and people with multiple jobs being unable to play a diversity of roles because the lockout system caters to people who intentionally role-lock themselves.
If you make it to where people can only earn a job's tomestone gear by playing that role in the content the tomestones are earned in it would substantially eliminate all four of these issues.
For the first point, you actually feel like u are earning that job's best gear by working as that job.
Secondly, people would show they have enough knowledge of how the job works by being able to complete the content on the job that awards the tomestones.
Thirdly, it keeps people busy through the week if they desire to earn the tomestones for multiple jobs. For example, say the cap is 200 tomestones. You play one job and get your 200 tomestones for that job, you would also be able to earn the 200 tomestones for any other job you are able to complete the content for during the week so you're looking at increasing the amount of time needed each week to 'cap' your tomestones 2x's through 9x's as much time as would be needed for a single job by going after multiple jobs. So instead of capping in 2 days and disappearing for the rest of the week, a player would have motivation to play substantially longer each week to work on different jobs.
Fourth point, everything in the game currently end-game is based on the same generic lock-out system and people who want to enjoy more of a diversity of the content by playing different roles are at a disadvantage accrual-wise compared to players who refuse to do anything but role-lock themselves to a specific role for all content. If you make the acquisition of the best-in-slot tomestones job-specific, people who play a single role do not accrue any slower gear for that specific job than those that play a diversity, but it gives people who desire to play a diversity of roles an ejnoyable reason to do so.