I don't know how long ago they added the hover infoboxes, but I also noticed those. But that's a relatively small feature, at least from my perspective.
Sysadmins are paid to make sure wikipedia doesn't have random downtime. Time spent on bugfixing should only be noticed if someone screws up.
If you want to see what people are doing - the git repo is public. https://github.com/wikimedia
I'm guessing I'll end up either using an extension or writing something up in Greasemonkey. There might even already be a userscript out there I can use.
I'm pretty sure there's a public roadmap somewhere, and you could always follow through their bug system or PRs. Everything is developed in the open, even the infrastructure (disclaimer: I founded wikimedia cloud services, and opened up the infrastructure development).