Spells maybe simple and only have have a hand full of them, but people still have no idea on how to use them.
First, if you are only spam thunder > thundra, with thundaga when your mana and crit buffs are up; you are not playing your BLM/THM to its fullest. That what I do when I'm low of mana and trying to get some back.
Most people don't even try to use the debuff effects of their spells. Aerora dispels enemy buffs, too many CNJs don't know it can. Blizzara binds enemies and is a fantastic crowd control to use; alternate it with sleep to keep enemies under control longer. Yet, I see BLM/THM die to stuff because they don't think to bind things and walk away... all the time. I see people flare monster then wonder why they can't sleep it. I could go on.
Spell lists maybe limited, but people still have little idea on how to use them. Honestly, I fail to see how having a huge spell list of spells, that I won't use,will improve my spell casting experience. It will be like other MMOs that had giant spell lists, I had the best on my bar, the rest collected dust.
To each their own though.