I think we should spent more focus on improving the UI capabilities if we want to be able to compete with other Open Source and Closed Source products. I still see many components with limited and/or inconsistent visual design or user interaction options - at the same time it is quite hard to either fix/change these issues (e.g. through CSS fixes) or build new custom components without the restrictions OH puts onto plain F7 components.
I had described more details in this post when I tried OH3:
https://community.openhab.org/t/oh3-ui-some-great-some-not-so-great-design-decisions-and-prioritizations/115165
Some details may have changed since then, but the more fundamental issues persist I believe.