In HD it was possible to spectate AI games, but the DE doesn’t allow human to join as a spectator to an AI game. I assume this is just an oversight and devs just forget to add this feature.
While I acknowledge that this is not the urgent issue plaquing the game at the moment, I’m still kinda missing this feature.
Hello ClosingIsland58,
Try replacing your own playerslot with an AI the same way as you would choose an AI for any of the other slots (2-8). That way you should be able to spectate that AI, to see the entire maps you can use the cheats “Marco” and “Polo” if you so desire. 
I hope that helps!
-Promiskuitiv
That’s what I’m currently doing, but it’s more like a hacky workaround compared to actual spectator controls.
That way I’m sharing the controls with AI and I’m not able to change spectator view to other AI players and see how much resources they have, what they are producing, etc.
Since these AI games can last rather long, it would be nice if it was possible to increace game speed to 4x or 8x just like in the HD.
Also, a minor bug report. If I’m “spectating” by sharing the player control with an AI, I can control units, start rsearches and create units, but if the AI has queued units, the "“create unit” and “research technology” buttons from bottom are no longer available.