Doing some work on a new site using Whidbey, and I came across this:
http://msdn.microsoft.com/asp.net/whidbey/beta2update.aspx#ASP.NET_2.0_Compilation_Model_Changes

YES!!! Whoever says MS doesn't listen is definately wrong. Quick recap: ASP.NET changed it's project system/compilation model to better suit people who think HTML is a programming language. Good ASP.NET developers pushed back... hard. The “Web Platform and Tools“ team nicely listened. Yey!

The blessed article is a bit terse, so I've provided common-language translations (sarcasm and jest ahead... it's just because I'm so relieved, no offense intended):

“In response to significant customer feedback...”.
Translation: “We spoke with professional developers, instead of just going after the “PHP is teh r0x0rs” group, and the “I know HTML and thus am a 'Web Developer'” group.“

”The goal is to improve the code-behind and code-separation experience and enable the partial class paradigm to be used to improve the code-behind experience while continuing to maintain a syntax and functionality that is very similar to ASP.NET 1.x.“
Translation: “We fixed the compilation model.” 
Note: Wow, that's a really long sentence. And they even used the word “paradigm“. Wow.

“As a result, it makes upgrading of v1.x projects even easier and further reduces new ASP.NET 2.0 specific concepts.“
Translation: “Customers told us backwards compatability and migration was actually important.“
Minor correction: “upgrading of v1.x projects *possible* and further...“ (Yea, I had zero luck upgrading projects. Yet I could open VC++ 6 projects with VS2005 and compile and deploy to client systems with zero problems.)

“In short, this change enables developers to continue to pre-compile ASP.NET pages for significant performance gains while still being able to maintain the .aspx markup content separate from the binary.“
Translation: “Now things work like 1.1 again.“

Wow, this is really, really great news. I'm thrilled. Can't wait to get Beta 2, even if it means having to redo a nice amount of code.

Oh, BTW, they shortened the special directory (the Vile Code directory) prefix from “/Application_“ to “/app_“, and rightly canned “/Application_Assemblies“ (which was the “/bin“ replacement). Why “/Application_Assemblies“ was ever a good idea apart from consistency is beyond me...

Even so... something gives me the feeling that the compatability part of their team is somehow very much different from say, the Windows Shell team :).