I've been ranting and nagging about this since the start of the beta, even started several threads here about it. Nobody gave a shit.
And suddenly, out of the blue, everyone wanted it after AmiPolizeiFunk wrote that piece of art. Some people even condemned Relic for not having this in the game since day one even though they probably didn't write a single word here or elsewhere requesting this feature.
I really hope that this observer mode comes with a lot of options and that it is a benefit for everyone and not just the casters. It kinda defeats its purpose if you can only use it in custom games and not in automatch.