I notice you're not using any gameprops on the ground after the spell has faded... any particular reason? Don't get me wrong, the effects are 100% top notch (and ten times better than stardocks). For example, you could add smoke or fire on the ground, or ice crystals that last for duration:x.
the only real reason is that i can't get it to work as i want(like change the tile completely), i can actually make some particle stay forever after the spell is casted by simply use the "emitter is indefinite" function like you can see in this screen:
that is a result of 3 fireball, but with the "depth bias" active any unit who step on it will be covered by the burned ground 
anyway it will work great with smoke and other effect (at least as long as i don't cast another spell on that tile)
Wow, these all look great - really high quality work, much more like you'd think the spells would look. I have to very selfishly ask, when are the air and eath mods coming?
i can't realy say, but i hope to realease them realy soon ^^
