I honestly understand the frustration of people who'd like the job to be 'normal'. I wouldn't mind if it was, really, but I try to enjoy it for what it is - and on that regard I don't dislike it, however...

Blue Mages need a better daily "ready-to-play" content structure. Something that you can log, swap to the job, and do right away without the hassle of setting Party Finder groups that never fill when we're not at their update patches. When you log in and switch to a regular job, you can do roulettes, you can do side content duties, you can do the MSQ if you're due, you can do PVP - you can join those almost instantly, maybe save for a few minutes on a queue.

The only real thing a Blue Mage can do readily is the Carnivale. However, almost all of those repeatable objectives are the very essence of puzzle based fights, and to me personally they aren't fun to redo. If you don't need Allied Seals anymore, there's very little reason to keep reclearing them.

The solutions:

1) The easiest one - let Blue Mages get credit for the Log objectives if done solo. I'd say it's even more engaging than with a group because even with Basic Instinct, you still need a good amount of strategy and spell selection to deal with the trash and bosses, since the 1-hit KO spells have cooldowns.

2) Been said again and again by others, but let Blue Mages solo Deep Dungeons for their own achievement and scoreboard. If balancing against other jobs is a problem, there's a solution that'd require more production involvement: the caster can only use an exclusive Deep Dungeon spellbook that you fill as you go with enemies, bosses and maybe RNG silver chest tokens.

3) Add Blue Mages to the PVP roster. There's no conceptual reason why they would not given that every single job is drastically changed to fit there - sometimes even straying from their PVE job fantasies.

Every, or any, of these would add a new breath of life into the job, especially outside of their patch update periods.