There was an enormous amount of hate against the interface in the first game from a lot of people. It would also double (at least) the time frame to implement the interface. I'm glad that it's mostly an anesthetic thing on the interface, because I could do something like desaturate the icons, for instance.
That said, color is a really useful tool for catching the eye. And if the buttons are overly large on your screen, you can adjust the ui scale down in the settings; I'd be interested to know if that affects your opinion any.