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.