Areulion Sol should be able to stun instantly or in a shorter time

It makes no sense to me that Areulion can not stun instantly. His stun is like Anivia's but Anivia can stun instantly. Sol needs this more then Anivia. It is just a bit unfair that sol can't instantly stun. You have no attacks except the stars and his ult. His stun you cast and you have to wait a second to activate it. The stun is a great skill but if you can't instant activate it leaves you with nothing you can do if someone jumps on you. He should be able to defend in those situations. At least cut activation time down a little if it cannot be instant. Just a thought from a fellow who likes Sol alot.