What do you think of these suggestions - not being able to stand up while Stunned, and Stunned always breaking spells with casting time?
I think both knocked prone and stun should interrupt a spell being cast like fireball have a casting time of 1 turn, if I stun him he should lose the spell (meaby regain some mana if the dev's feel kind).
I think stunned characters should have to wait till they are unstunned before they can spend a turn to stand up, after all I did use severe amounts of resources to knock the poor lad prone AND stun him 
Edit: That said, I do favour games that allow me to combo up abilities, if I find some extensive setup, I want an extensive reward 
Sincerely
~ Kongdej