The gold standard for UI for me, though, is still Wings3D (based on Nendo). It has way better UV unwrapping support than anything else I've tried. It is as good as it is specifically because the functionality it aims at is quite limited.
Sketchup gets an honorable mention for UI, but the scripting and geometry it makes is such garbage I can't recommend it.
What it's missing really is some of the universal, underlying data flow architecture that the likes of Maya and Houdini had from the start. But it's getting there.
Could you elaborate on that? I'm not sure I understand what you mean by "data flow" in the context of a CGI package.
You'll generally see these pipelines depicted as editable, directed graphs (DAGs) in the application. Blender uses DAGs for a number of things - eg an image compositor, and for shading networks. It also provides modifier layers (like 3DS MAX) for geometry transformation. But it doesn't go down to the core of the application which is why you can get some problems when it comes to certain tasks in animation for instance. But they are working on this.
It's a bit like all these various architectures for the web - Flux, RxJS etc. They're making explicit the transformations and dependencies that happen, by means of a data flow graph (even if it is not visualised). This usually means less surprises and more opportunity for optimization.