First off: I always play unlocked camera. 100%
Purple has a much worse camera angle not due to the UI for me, but due to the fact that the camera isn't looking straight down, it's looking angled from bot to top. Which means that nomatter WHAT I do with my camera, I can see further towards top than bot.
So in order to do some of the skillshots that I can do as blue with my character on the same screen as I'm aiming... I have to do from purple with my character completely off the screen, limiting my situational awareness.