As I've encountered in many tickets in the tracker, when @shoogen was active (way before my time), there was a lot of communication happening upstream. The evidence is in the abundance of upstream bugs he filed. He also posted on their forums. Now I'm not saying there is a total absence of dialogue happening, for example I know that @vejmarie has coordinated upstream and others in the community have as well. But it seems it could only benefit FC more if the communication channel was used more frequently and accessibly.
BTW, I was reminded by this by something @tanderson69 wrote in a recent thread
This makes a lot of sense. Especially given we have these open issues: