> headline is implying (some kind of hugely complex, hard-to-create UI)

Making anything simple is HUGELY complex. It took them years to get what they wanted and it shows. I think complex UI is actually lazy work. Space 4X games have notorious UI. Endless Space 2's interface might be much simpler than others but I guarantee you they put more time into refining their interface.

Being able to explain or create something "simple" is perhaps the hardest part of creating, and is much harder than naming things in programming and that actually is perhaps is the hardest part.