I can't prog raids as BLU/BST, I can't do Deep Dungeons as BLU/BST, I can't do Ultimates (even old ones) as BLU/BST, and most hilariously, I cannot take the jobs specifically tailormade to function really well in open world exploring/finding monsters to fight, into Eureka/Bozja, 'openworld instances' with many monsters with unique skills and abilities. THAT is why they're 'limited'. I still have no idea why BLU can't do Eureka, the absolute easiest of 'it's free content' for SE to throw out for people and they didn't do it
OP, you can be reductive about 'how the job would play if it were a real job' all you like, it just demonstrates a lack of creativity/imagination on your part.
For example with BLU, they could have done a system that allows the 7 different '220p conal AOE' spells we have to all function as spell glamours, with a base set of skills that you learn from totems as you level. Apparently 'you hit level 80, here's a totem that teaches you the skill' is acceptable as a learning source, after all
One of these things is not like the others
edit: also lol if you think BLU isn't beholden to the 2min meta, it was part of the 2min meta even before EW gave it to every job