tesb : if you'll pardon my comments :
effects : good ones. (maybe stars : none, 1-centered, 2-placed as now in the 2nd icone)
range : remove 1 star in each icone (like Drill 1 has no star), keep the stars that are on top of the "knife thrower guy".
targets : no need of stars, the number of guys being easy to read. If you make stars, maybe you should keep only the second icone, and have : no star/1 star centered/2stars. (it would allow for some spell having, without any extension already a multiple target, and each promotion adding some more target, but not being defined by +1 or +2 targeted units)
color of "aura related icones" (you'll have to check that with someone with a bit of autority) compared to the actual color codes
Deep blue is related to combat modifiers (, firsts strikes....)
so either make it reddish as "chanelling" to show it is arcane related
make it pinkinsh as "spell extension" to show it is spell-related
make it glow, light blue, light green or any other color if you think it is better.
or keep it deep blue as it is a nice color and it feels "official".
In my opinion, icones should be nice to look at, but more importantly they should be really easy to read, especially when if you imagine it on a lvl 20 guy, with more than 25 promotions. If it's your guy, you know him. if it's the AI's guy, it should be easy to read so as to know how dangerous he is but you can't "zoom in" it's promotions.
on it, i will update this post in some minutes

edit: this color scheme?