2D Wall Placement Mechanics - Select Direction

There are a few champions who's wall placement is, "outdated". I'm referring to champions who are forced to place walls tangent from where they click, these champions are:

As it stands, these champions are forced to place their walls perpendicular to the direction in-which you cast the wall, giving it limited use, and sometimes causing more harm than good in the case of Anivia. It would be very useful if these champions could modify the direction their walls faced when they used them.

This allows these champions to become slightly less positioning dependent enables them to use their walls in new and interesting ways... For example, Jinx could lay her chompers over a wall, but have them still face the appropriate direction to block the way. Or Anivia and Karthus can separate a team fight with a completely new dynamic. And Jayce can line up his gate so he and his allies can run through it the whole way, refreshing the buff all along, or to catch the buff on one side of a U-turn and then refresh it on the other side of the turn.

This is a serious change and should be treated accordingly, it may require balance changes to effected champions (IE slight range reduction of skills in question) but I feel it will add a lot of new gameplay opportunities to the champions, not only giving them more diversity, but adding power in a new and exciting way, enabling plays that weren't possible before.

PS: Mechanically, bosh Yasuo and Azir are exempt from this topic because their placement mechanics are designed to push outwards from their champion, outwards, also, both Thresh and Veigar are exempt from this topic, as their walls are designed with consistency in mind, and more closely resemble a circle, making a change less meaningful.