What about adding a model to the affected unit? The example I'm thinking of is if a unit gets hit by an entanglement sort of effect, and vines spring up from the ground to wrap themselves around the target...
Hmmm, Ok, so a model with a 'start-anim' (vines coming up), 'idle-anim' (vines with target entangled), 'end-anim' (vines going back into the ground) ... there are some issues to consider I think, but most of them effect the modder more than the engine programmer... let me think on it, I'll open an ticket.
By the way, I couldn't find a ticket for the "apply effect" or "cast spell" skill on trac, and it seems to keep falling through the cracks. 
Yes, cast-spell does keep slipping through somehow.... ticket #186, target 0.4.
