Most of the development isn't reader facing. It's editor facing (WYSIWYG editor/etc, toolforge), community developer facing (wikimedia cloud services/toolforge/etc), improvements to the infrastructure (CDN data centers/DR/etc), wikidata improvements (which you see as a reader, but don't know you see as a reader), and lots of other things.
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).