You might want to look at theses blogs where other people has created their own spells using the "spells as powers" approach.
http://islandsofwar.simulatoralive.n.../colleges.html
https://enragedeggplant.blogspot.com...ell-index.html
I don't completly agree with some of the builds, but they are great sources. I really appreciate their job!
I recommend you giving a try.