For me, an interesting language development would be finding ways to make managing dependencies more... manageable. We've seen a rise in systems for packaging, distributing and consuming code written by others. However, still a significant part of maintaining systems is spending time on upgrading dependencies, updating application code as things are deprecated, responding to CVEs, etc.

I think there's interesting research and ideas to find in this area, that could lead to a productivity boost. One example idea (I'm sure there are better ones) would be allowing simultaneous use of multiple versions of a library. E.g. This dependency I'm consuming uses CommonLibrary-1.2, and this other dependency uses CommonLibrary-2.4, but they can both get along just fine without having to find some combination both dependencies can agree on.