Class changing, are we unique?

[Mysteltain]

TBF a Level 50 SMN can also use Teraflare despite not getting the abilities of Bahamut until 58

And let's not, further, forget that it wasn't even until Heavensward that every class got a unique LB3. So basically what we have is one of those odd lines drawn between "what is canon" and "what is gameplay".