Time to throw my hat in the ring and line out a way of balancing out Alliance Raid roulette to not be as horribly skewed toward Crystal Tower raids.
- Assuming a brand new player, each time they complete an expansion's last quest (for x.0), the alliance raid roulette gets locked until you complete that expansion's alliance raid series. And I don't mean "just do Void Ark after 3.0 and it's back", I mean the entirety of the Mhach raids. Once that's done, until you complete the 4.0 MSQ, the roulette is open again. As soon as 4.0 MSQ is done though, time to do the entirety of the Ivalice raids to access it again until 5.0 MSQ is done.
- With the above in mind, make an item level requirement depending on the level range you're trying to go as. Have a level 50-59 job you want to run as? Cool, Crystal Tower is all you can do anyway, so be at least i90 for World of Darkness to be included. (Crystal Tower raids are required for MSQ anyway, so why limit the roulette to just 2 out of 3 of them via item level cheese?) Trying to level a job in the 70-79 range? Can't lower your item level for just Crystal Tower, you have to at least be the item level for Orbonne Monastery (365). Again, this assumes the above point, so this would mean you have the possibility of any Crystal Tower raid, any Mhach raid, or any Ivalice raid.
- Or maybe you're already level 90 on everything and just want to join for the tomes and fun? Since Aglaia is the only 90 alliance raid at this time, you only need to meet that item level requirement (565). Then once the next one releases in 6.3, presumably with an item level requirement of 595, the roulette is locked until you clear the second 90 alliance raid, then it'll require i595 as opposed to i565 like it did before. Then it happens again in 6.5 with the assumed requirement of i625.
Effectively, this would make every alliance raid a requirement to even have access to the roulette. I'm sure this comes with its own can of worms, one that comes to mind being that requiring not-required raids to have access to a roulette may result in less people even bothering to do alliance raids at all. In a worst case scenario, I can see that being the case. I'm even sure there's better ways of boosting the possibility of more than just Crystal Tower.
If anyone can add to this suggestion or even explain another possible glaring negative to this that I'm not aware of, without outright dismissing the notion with no further input, I'd appreciate the insight.
Sincerely, a level 90 player that does roulettes for fun but doesn't even touch alliance raid roulette anymore unless helping friends level their jobs, and even then we don't really bother with it unless we really want the xp alongside the mind-numbing Crystal Tower roulette