Adopt Metro UI Design Philosophy: Fast and Fluid
Please adopt Metro UI philosophy: "fast and fluid"  in VS vNext by making all potential-to-be-blocking-UI operations as async as possible. I know VS is not a touch-based UI, but "fast and fluid" is general concept that can be applied to UI such as VS too. Fluid also implies to be smooth: smooth in UI transitions, scrolling text editors/designers, animation in various possible places, etc.
Make asynchronous APIs for accessing various VS features so that they are not blocking VS UI. Quoting Miguel de Icaza, "With WinRT, Microsoft has followed a simple rule: if an API is expected to take more than 50 milliseconds to run, the API is asynchronous." , I think it's important to provide such a cut-off criteria for determining whether an API/operation should be async or not.
Lastly, please make UI-related operations to use less CPU resource. CPU resource is a precious one that is meant to be used wisely, and not "abused". For example, in my bug report , I notice editing in XAML editor use a significant amount of CPU usage that could degrade overal system performance, not just VS. I've noticed even scrolling in text editor could fall into such trap.
 "Async everywhere: creating responsive APIs & apps" (http://channel9.msdn.com/Events/BUILD/BUILD2011/PLAT-203T)
I don't really care how fast or slow an operation is, as long as it's not blocking the UI thread and making me stare at the "toilet bowl of dooom".
Change everything in VS to have neither synchronous IO nor modal dialogs. Period.
Every operation should have in-progress notifications and error handling and should always leave the UI in a responsive state.
Gabriel Monteiro Nepomuceno commented
Plasedo this visual studio have the same style since forever we are in times that we want less **** less chrome just give us what we want in hand