"Wow, this file is really popular! Some tools might be unavailable until the crowd clears. Try again. Dismiss."
This sucks because comments don't show when this happens, which is the whole point. Hopefully things will die down later and the comments will be visible again soon.
Take a look at Angular Announcements[1] released in November 2014. The warning message is still visible today. I think it's a bug or something because once your file get that warning message it remains forever.
[1] https://docs.google.com/a/ideveloper.ro/presentation/d/1fE0P...
https://docs.google.com/presentation/d/1fE0PW1FMlYU9Xhig_QIG...
I wonder if the bug you're seeing is something that is specific for Google slides in presentation mode.
First, really sorry if the comments still aren’t showing up. I really thought the doc would be working by now, but it isn’t.
The plan now is to wait a bit longer, and then tomorrow if there’s still no luck with Google Docs, I’m going to move the project to another service.
My gut is telling me to use medium.com for this. Medium won’t die under heavy lead, it’s well designed, and it also has some great commenting features.