Lissandra's R- Frozen Tomb

Hey all ! have been playing Lissandra a lot lately and I am having alot of hard time cause of her Ulti. the thing is when I go against melee champs I am forced to fight so close to them that sometimes i miss-target my Ulti. e.g. a Zed just used his ulti on u and u want to Stun with ur Ulti to make his ulti useless and instead of ulting him u ulti urself casue he stands so close to u and then u find him waiting to finish u off. another example is u going into a team fight and u want to Ulti a carry but u miss click again and ulti urself cause there are so many champs in one place. ofcourse another problem is that u miss click the enemy champ u want with another one but that is a another whole story :P.

so my Idea is that Liss Ulti should only target Enemy Champion's if u normal cast it by pressing R, and if u want to ulti urself then press Alt - R.