I'm a rooster fan, but I'm also a realist and while I agree with most of what you've written my experience of what roosters actually do when the shit hits the fan is rather different to your description.
I've had lovely roosters, good with the hens, good with people but when that hawk comes...
No you don't need a rooster to free range hens.
Someone in this thread described them as a speed bump, while that's a bit unkind there is an element of truth in it.
The roosters I've had here (I've had quite a few) do save some of the hens from some of the predators. The downside is they die...