Top team seriously disadvantaged. Bottom gets big advantage!!
Because of the point of view of the game (LOL) the angle of the camera/perspective of landscape gives a significant disadvantage to the team positioned at the (top right of the map), and a huge advantage to the bottom team (lower left side of the map).
The most serious issue is distance/range calculation in perspective. A player who fires a skill shot "up map" has a shorter distance to reach its target. Similarly, a player who fires down map has a larger distance to reach the target.
for a better visual example, lets examine a skill shot template.
Lux 's "E" skill shot has a straight directional template. when the skill shot (template) is aimed "up screen" the template shortens: as it should to follow the rules of perspective. Unfortunately for the top team the skill shot travels a shorter distance "up screen" and hits a target much faster.
Similarly if Lux was aiming "down screen" the template is extremely stretched out (again to adhere to the rules of perspective).
When the shot is fired "down screen" the distance is much greater to reach a target, and the opposing player has more time to avoid the incoming skill shot.
Try aiming in both "up and down screen" directions while using "locked camera" the concept is beautifully illustrated here.
The template stretches so far "down screen" that the end of it disappears off screen. And "up screen" the template is so short it, the end appears no more than a couple of champion widths away.
Also, a player who is aiming "down screen" is more likely to lose a target behind the HUD, map, etc. at the bottom of the screen. Where as the "up screen" direction has little to no obstruction.
There are plenty of more issues caused by the perspective view, but this effects game play drastically.