It's probably best not to go by FFXI's way of using suffixes anyway, since FFXIV's spell list isn't as big as FFXI's. If people really want to separate the AoE spells from the single target spells (to make it less confusing or whatever), why not rename the AoE spells? (with the exception of WHM/SCH spells... unless they get a fourth Aero/Miasma)

Fire II - Scorch, Blizzard II - Frost, and Thunder II/IV - Storm/Stormga (Thunder III will also be changed to Thundaga. If SE actually did this, then I'd also be fine with Thunder not being renamed to Bolt. Thunder and Storm).

That's just an idea. I'm fine with numbers, anyway.