1. No one’s asking you to not file a report for battery concerns. I only suggested it be kept to a minimum on the beta threads which is not a place Apple checks for bugs.If you enter a beta program only to avoid reporting bugs you find in your unit, including battery life issues, it makes the beta program pointless. Complaining makes even less sense in a stable version, because unless they're serious bugs, they won't fix them for at least a month.
And of course, besides reporting the bugs I've found in the relevant forum thread, I've also reported them to Apple, which is ultimately the right thing to do. All the bug reports I've mentioned have more than 10 copies, so unfortunately, they're not isolated incidents.
2. A stable version is going to be on millions more devices and like you said for a much longer time. So any issues affecting battery life is going to affect a much larger sample. And more data from those affected devices makes it easier to find a fix unlike a beta.
3. Stable means finished software which means they have a higher priority for the above reasons.