1) There's already patch 2.06, and 2.07 is in the works, as one could have guessed from johans article.
2) johan is on the design team
3) I've
never seen the AI cast the same, unstackable spells with target "caster" more than once. Unless the commanders are scripted to do this. Keep in mind, though, that some spells do stack with themselves or each other.
4)
".. in the 2.07 patch the spell AI will drop the estimated worth of some protective enchanments. As it stands it will also value protective enchanments less and less as turns go by. .. think this will take care of most problems. Even if for some reason the AI doesn't recognize an enchantment already done, it wouldn't cast the spell again after some (5
) combat rounds.