I'm still getting used to it myself and don't see much difference in terms of functionality, though I do like the new look of it with one exception. I don't know if it's just me, but the custom colorization for the widget does not appear unless you hover over it. I'm about to submit a support ticket for it, though.

I've just asked Support about it and have been told it has been changed "to make positivity of scores more immediately obvious."
I find this a bit peculiar, because as you say, you cannot see any colorisation until you mouse over the chart, which makes it LESS clear, in my opinion. It is a step backwards, and I'm not very happy about it. The product specialist who replied to me filed a complaint on my behalf, and I would recommend others do the same if they don't like this change.

Maybe there needs to be a fallback option so we can choose "New" or "Classic"

https://www.qualtrics.com/community/discussion/comment/29299#Comment_29299Good suggestion Peter! I created a Product Idea for it! Please vote
https://www.qualtrics.com/community/discussion/12048/new-gauge-chart-widget-new-vs-classic-look-option