Beauty is in the eye of the beholder, and I wholeheartedly prefer “classic” nice 3D colorful rich user interfaces to those “modern” flat bland UIs.
In other words, those “modern” flat UIs are a regression to me.
Just consider how nice is Visual Studio 2010’s UI if compared to the Visual Studio 2015’s one (you can click the screenshots to see them in full size):
Also Windows 7 icons (from the previous VS2010 screenshot) look much better to me than those dumbed-down bland icons of Window 10:
Don’t get me wrong: there are important improvements under the hood in Windows 10, and the Visual Studio 2015’s C++ compiler and standard libraries are better than those that ship with Visual Studio 2010, but this more recent UI look seems a regression to me.
To make everyone happy, why not just implementing a UI style theme selector, and providing both the “rich” and the “flat” styles, so that users can choose their favorite UI style?