So, I started playing Dota a few morths back, and I noticed my friend wanted to coach me. There is a special position for a "coach" in the main lobby. The coach only sees what the team sees and has no control over the actual gameplay. I think this would be a huge help not only for new players, but for starting teams who don´t have a big budget to spend.
It´s relatively simple to make such a "role". It would basically be a spectator, who can only view the team he selected to coach, and would only have vision of that team. If you think it brings unfair advantages, or other complications feel free to criticise my idea.