Would I trade some of the depth of features for a better interface?

But that's really not the tradeoff. A more consistent interface takes less total time to write and maintain than one that has one-offs for every situation. Inconsistency makes future development slower.

And we only see the tip of the interface iceberg. I find it highly unlikely that the internal interfaces between components are any better. Everything about Dwarf Fortress gives the impression that their source code is probably a nightmare.

Which doesn't matter, of course, so long as it runs -- until you want new features and progress grinds down to a crawl.