I'm in the camp who dislikes the new colors and icons. It's the one aspect of 2017 that I'm disappointed with. (Otherwise, I think 2017 is definitely the best release to-date).
The new icons are actually really bad in my opinion. As everyone in my circles complains, gray on gray is hard to see... and the lack of overall color contrast in the icons forces your brain to pause longer while trying to distinguish different icons. Take, for example, the Loop and Ring icons in the Edit UVW window. In the old dialog... those icons are all very distinguishable right-away. In 2017, you have to focus and decide which is which.
But even worse, the icons have created a new batch of confusion. Take the new snap icons in the snaps toolbar. I asked several people who do not use Max to guess the meaning of the snaps icons in 2016. Except for Pivot, almost all guessed correctly at what they meant in 2016. When I did the same for 2017, only snap to grid was guessed correctly.
Worse still, the new icons add inconsistency. The new snaps icons now completely reverts many years of Snap to Edge to now be Snap to Face. Other icons actually baffle me, like snap to midpoint, etc. But it gets worse because other icons inside Max still utilize the traditional meanings... like the Editable Poly sub-objects no long match (Edge in Editable Poly is the Face icon for snaps. New Edge Icon in Edit UVW window is more like traditional edge, etc).
I absolutely love Max 2017 in general. But my personal opinion is that some really poor decisions were made with the icons and colors.
I personally want to update all the icons to the legacy ones, but then again it will cause pain when making documentation, videos and screen shots for educational purposes... and students are suddenly confused because what I'm showing isn't the Max they are using. So I'm going to trudge along in the new UI... but I'm crossing my fingers that enough people complain about it to make a classic icon view a standard option.