This is great. Makes me think of the change from Visual Studio from 2008 to 2010. They made a very good IDE into a slow, unreadable mess with much less functionality just to have a “flat” interface. I still don’t understand that nobody at MS noticed how bad that change was. Or more likely people weren’t listened to. Even after almost 10 years they barely have caught up to what they had with 2008.
It was a major rewrite of large chunks of the interface from native C++ using raw Win32 calls (and said C++ was written back in 1996 in many cases, to the point where it'd do AddRef/Release calls by hand sometimes - forget RAII and anything that you know of modern C++), to C# and WPF. And it was necessary even solely from an engineering perspective, because adding features to that original code was becoming a huge pain.
The result was worse in pretty much every way. Graphically (whole idea was it to take out all colors from the Ui? I don't know anyone who thought the 2010 UI was a good idea), Slower, less customizable , less features (for example they removed macro recording).
For example, the color was a UX design decision - WPF made it possible to do theming easier, but even so, doing it instead of using stock controls actually required extra effort. But, speaking of colors and preferences - when VS 2012 went with its "black and white" color theme a couple years later, a lot of people actually demanded specifically the return of the blue VS2010 theme. Which is why it's still there today.
As for macros, it was essentially on life support for several releases prior to all that. It was essentially a separate subproduct, coming from Office originally (since it also uses VBA for scripting), but forked ages ago, and not well maintained... and it was completely broken by changing the GUI framework. So the choice was basically to rewrite or drop it at that point, and a rewrite would require substantial work - on par with the rest of the product, really. And with <1% of VS users using macros at all, it was very hard to justify a rewrite.
I would agree, though, that WPF was not a stellar framework at the time. But, ironically, VS adopting it made it better in so many ways - for example, WPF font rendering was fixed (to be less blurry) largely because of user feedback in VS2010. Perf was improved substantially, as well.
