I look forward to a redesign of some, but not all, of the system preferences, so that there are three distinct styles of preference pane with different partially disjoint sets of options, that you have to go hunting through to find the setting you want.
Ehh I bet that will happen again. I can just picture some PM somewhere:
"Well most of our users aren't using those settings, why bother putting in dev time to update them. Lets just push out the main UI update as an MVP then come back later* and update the more obscure settings."
I know you weren't referring to Narrator the screen reader here, but I can't resist. While I was on the Windows accessibility team, which owns Narrator, we actually did phase out the old Narrator settings UI in favor of the new, UWP-based one.
Only three? I'm pretty sure I can already count at least 3 UI fads that have come and gone in my Windows 10 install. Somehow it's gotten worse each time... I'm trying not to sound like a grumpy old man but it feels like each revision is more geared towards mobile device users and the product sees a corresponding loss of flexibility and configurability.