1. We're almost certainly going to keep the aggressive kernel updates. It's very expensive to maintain a long-term kernel fork with bugfixes, and users benefit from the constantly-rolling hardware enablement. That said, we are working on making automated testing of these updates better, so we can block ones with serious regressions. I think the experience you are describing is likely due to proprietary drivers not matching the new kernel; we have some work in flight to keep the old kernel the default if you have proprietary drivers installed and they aren't updated to match. (Except in the event of a critical security bug.)

2. Have you looked at the font changes in F24? What do you think?

3. I know the GNOME team is working on battery life. I haven't experienced random freezing, but for subjective responsiveness, I recommend the Impatience extension which shortens animation time https://extensions.gnome.org/extension/277/impatience/ (I've jokingly suggested we install this by default with a timer which shortens the animations the longer you have it installed.)

4. Thanks; I'll definitely consider that.