There's more to UI than just contrasty icons/text. Even HE's dashboards suffers from this (just look at the stock switch icon - white text on a yellow background when on). Most people (here at least) are focussed on ease of use ie not always having to refer to a document or bookmarked post to figure out how to do something.
Also dashboards aren't only about controlling switches. I use my desktop dashboard for an at a glance view of everything plus showing video feeds, status, weather, power use etc. I also have a nest hub on my desk which does precisely that plus a few switches to manually control certain things. In this context a better UI would be very handy in organising and displaying data.
As would most of us 
. But painful as it is, it's a once off task anyway so TBH not a dealbreaker, Anyway for more customisation outside of one of the various apps out there you can check out using CSS here The Noob's (in)complete guide to CSS for Hubitat
