Its really difficult. The exact placement of individual trees in the game matters a lot and it affects line of sight, which is a key component to Dota. If you flipped the view, not only would it just be weird, but what is visible can change I think based on the camera position. A tree that blocks a path in one camera position doesn't block it in another. A single tree's position sounds trivial, but navigating them is crucial at mid and high levels of play.

This is really perceptive and on point. I think something a lot of casual observers miss about Dota is it's a game of momentum with very small edges that accumulate. Compared to the other MOBAs it's the game that punishes you for a single error far more harshly.

It certainly is confusing. I remember that someone once made a video with the flipped map and most of the comments were about how weird it appeared: https://www.reddit.com/r/DotA2/comments/5rmbd3/

However, I wonder this is something that people would get used to, if they played it for a while. As far as I know, it was never seriously tried anywhere.

So, I suspect why they haven't gone with an approach like that is they want to preserve the layout for spectators. Dota is the biggest purse in all of esports, and they take the spectatorship quite seriously as a result.

as i recall, spectators receive game data, not a video stream. you can spectate in VR.

so during real tournaments they could just broadcast from a spectator in the “standard” view.