I think spells that work on several rows make sense. We can always decrease damage down to 1/4 or even 1/8 to make rows more important. And only super rare attacks will have true pierce.
Basically, I've yet to see a game with spells but without mass spells.
As for gui, I mean something like
this (I'm not an artist at all

). When you select an element, you see list of spells sorted by spell power (we even have it in spells properties, it's effect value).
Even this already will be more intuitive and will take less place in BE gui. And I'm sure Gismo will make even a better one
I'll start to work on classes then (half of Touhou pack #2 is ready, but it will wait for another coding pause).