I'm glad they didn't allow you to learn spells while subbed. If that were the case, Blu would be like Smn was before the level 20 avatar battles: another job that required you to have another job at 75 to get it all its spells before you even start. The way they set Smn up as what amounts to a third tier job (a step even further than advanced jobs) was a mistake imo, and I'm glad they didn't do so with blu. Needing Sea access is enough to distinguish good Blues from the sea of other blues out there.