Observer mode

Hello, I would like to know if a Observer mode would be possible? Similar to Warcraft 3 and the games that came after.

I would like to watch AI vs AI games, preferably huge battles, without taking a seat (like warcraft 3). Watching Player vs Player duels would also be a thing!
I know there was a map that allowed this, but it was just one map, and it had to be prepared in a special way, just 1 observer, etc.

I wonder if this would be possible, even if a work around for all maps, like a Observer race (or "A observer" (so it shows at top of the list of races)), with special invisible invulnerable flying unit or something, no buildings (so they don't take game space(but at same time they don't lose the game?)). Perhaps the unit could have a few "spells" that allow to change custom range vision, up to all map. Maybe AIs could be told to ignore this race/Unit, as players already should do so.
Also an observer hero could have 0 HP and die?

We already have this planned, along with the ability to spectate after defeat.