1. LTS: In my experience, the issue that has caused most trouble is kernel version changes within a Fedora version. Why? Because drivers break. The laptop works fine just before the update. After the update, I get a blank screen. This has happened with different hardware, at least a dozen times in the last six years. CLI tweaking was needed every single time, to restore X or revert to a previous version. At other times, wi-fi no longer works after an update. At yet other times, random wake ups happen from sleep.
Maintaining the same kernel version (and associated stack) throughout a given Fedora release, in my humble opinion, can do wonders.
2. Font rendering: Yes, I realise that you have some patent issues. Please do the maximum that is legally possible. Fedora's font rendering hurts eyes after a few hours of work.
3. KDE: Desktop discussions can be subjective, of course! KDE's menu accelerators and accessibility help in minimising the need for trackpad/mouse use. In my laptop, KDE's responsiveness is uniform and smooth; GNOME experiences random freezes (Cinnamon has the same problem; so, I suspect it is GTK-specific). Also, on all of my laptops (HP, Dell), battery lasts noticeably longer under KDE.
4. Drivers: Yes, this is an Achilles' heel. Convenient installers for proprietary drivers go a long way in making the experience more pleasurable. Particularly, when we need to install, configure and support multiple laptops (including those of family).
Thanks, again, for soliciting feedback! I look forward to improvements on multiple fronts!