nginx opensource is more than enough to have a very capable solution.
All bells and whistles that are fenced off are more or less for people who don't want to bother engineering their infrastructure properly. Or can't do that for a reason.
The only thing that may really be needed is name resolution inside an upstream. But you can work around it in many cases.
If there is something you need in OSS - consider asking in a mailing list. Best case - you'll have a workaround (an unlikely outcome: feature will be moved to OSS). Worst case - you lose nothing, don't you?
It's quite difficult to get a decent feedback on a thing like a webserver. You can't add a pop-up window or email your users. You have to rely on an active feedback. A vague comment somewhere in the internet doesn't count as such.