Title says all basically. It would be super helpful when we jump into some competitive match. It could help to keep track of the players. Who plays who, who is recently in the team. It would give more credit to the players as well. However imo it should be toogleable feature in the options menu.

Suggestions of where it could be shown:

When there is not enough space it could float back and forward or just float in one direction to show again from another corner (you know like pacman, it is used in many TV with news). Or it could be shown in the place where hero name is now but it would change back to the hero name again time to time.

I also added 2 things: Hero color given by game is shown below hero name too. Also HP color now reflects side. Radiant green / Dire red / Neutral yellow. Again it would help to quickly understand what is going on without need of looking for this information all over the place (everything is where the player looks for most of the time). HP color could be spectator only (but imo it would be cool to give this option when playing too).