So I've noticed this actually can make a big difference. Maybe when I have time later I'll create some screenshots but I'll try my best to explain it right now, just so people are aware.
The imbalance lies in what's visible in from the brush in the center of the map. Imagine you're looking at the health relic. Let's shift slightly right to the purple side brush. If you stood in that brush as far over to the right as possible (towards the purple side altar), you can position yourself in the brush so that you can see almost all the way to the top lane.
Now let's shift back to the health relic, the slightly left to the blue side brush. If you stood in that brush as far over to the left as possible (towards the blue side altar), and position yourself for maximum visibility to the top lane, your vision gets cut off only half way there.
This gives the purple side a much better defensive position at the very start of the game, because they have full vision in the brush from any angle of attack an aggressive blue team could be coming from, and everyone can do it safely hidden in the brush.
If the blue team is in their brush and holding a defensive position, if they all want to be hidden in the brush, they sacrifice a large portion of vision from the top lane, and it's very popular for teams to rush the opposing side's brush from the top lane, they don't have time to react until the purple team is practically in the brush themselves.
It's just something that's been bothering me.
Edit: Adding screenshots:
Blue side brush vision:
Purple side brush vision