You're right, it's not in our current roadmap, which focuses mainly on features that improve data entry, analysis, visualization, and collaboration. Having said that, Mathesar could grow as a product and have a diverse set of features we've not yet planned, in the next few years.

A feature to build interfaces for internal admin tools sounds very cool, and while we cannot say that it's coming for sure, we'll definitely be discussing it. Please feel free to open a feature request issue on our Github repo, we'd appreciate it.