Anivia Wall

There are a few champs with abilities which allow players to completely change the layout of where you're fighting.

Jarvan's Ultimate can trap both enemies and allies in a small arena. It can help teams lockdown an enemy or it can be extremely detrimental if done wrong, trapping allies within its walls when they're trying to escape.

Azir's Ultimate creates a wall which pushes enemies away and makes an impenetrable wall for a short period that enemies are forced to go around but allows allies to pass through.

And now we have Taliyah, whose Ultimate creates an enormous wall which can completely cut off allies or enemies depending on the timing and cast direction of the wall. Like Jarvan, this can be helpful or detrimental to your allies depending on who gets blocked off by the wall.

And then, there's Anivia's Wall. Just like Jarvan and Taliyah it makes an impenetrable wall which can block off enemies or allies from taking a certain pathway. I've seen its incredible uses in fights, though most of the time I've seen it cast slightly off the mark blocking off allies from catching an escaping enemy.

However, Taliyah and Jarvan are both able to recast their Ultimate and bring their walls down early, which can be helpful if the initial cast doesn't go as planned, giving them the chance to at least try to correct their mistake before it can really mess up their teammates.

I feel like Anivia should be given this choice too. Being able to recast the ability and have it come down early, just in case it's placed in a not so desirable place as can sometimes be the case. Not only would this give Anivia players the same courtesy as Jarvan and Taliyah have if they accidentally block their teammates but it would probably make Anivia a more popular choice, as most times players completely ignore her wall ability in fear of a poor placement which can completely screw themselves or their teammates over.