Currently when I publish my site/app it stay's online. It would be better to drop an app_offline.htm during publishing so that my app doesn't behave in a funky fashion.

Please add a Report Viewer Control for MVC. Web Forms has one. Will not be able to completely move off of Web Forms until one is created.

In most case scenarios I'm uploading my website files using ftp and publishing tool is very uncomfortable.Meanwhile not all hosting companies are giving full access to their servers.
I remember in VS2005 there was an extension named Dispatch. It was very comfortable, right click, upload and file is on deployment server.
I think this can really save a lot of development time.

When deploying a site, the previous version should continue to run. If the deployment fails, the site should continue to run on the previous version. If it succeeds, the switch should happen after publication is complete.

It will be great if we can store session data both in inproc and out of process by an application similar to mixed mode session support. So that only crutial session data will be persisted out of process and some non crutial or temp ( depending on situation ) can be stored in InProc.

This support will be utilized by non web farm or web garden architecture.

Allow Web.Config transforms to be applied to a deployment package without a rebuild under a different configuration.
QA packages can then be converted to production release packages without fear of introducing any subsequent changes.
Add ins exist but would prefer to have built in support

As projects grow and transition from greenfield to brownfield projects .config files are getting more and more obsolete and dead stuff in them.

Do help me and show me what I delete of this.

Bundling is a cool idea, but it doesn't always play nicely with the ScriptManager when used in a webforms scenario. I would like to propose the ability to set a flag on the ScriptManager that would allow it to minify the combined scripts its serving.

I hate the fact that after publishing an asp.net web app, I need to remote into the server and encrypt connection strings and perhaps other sections of my web.config. It would be great if I could automatically kick off a post-deployment script which would do this for me.

Including a ressource using the following works. So Intellisense is available for the included ressource.

<script type="text/javascript" scr="/path/to/file.js"></script>

But as always, paths are note absolute. So asp.net mvc offers Url.Content("...") to dynamically generate the correct path to the requested file no matter where the application is placed in the web folder hierarchy.

So it would be very nice if you could make Intellisense also track paths specified in @Url.Content("") so that it is available for includes JS classes/functions.

If you're using *.ascx controls that you've created in your pages, it would be nice to be have a one click way to navigate to its definition instead of noting its name and looking for it in your solution explorer (especially for large projects).

There are other enhancements that would be nice such as automatically adding the @Register tag if the control is located in the current project.

Add please native support for Stylus - much better than Less and SASS/SCSS CSS preprocessor.

right now you have to run aspnet_regiis to encrypt the connection strings in a web.config. It would be nice to this could be built in as a part of the deploy process.

I would really like to have real time update on UI and javascript etc etc like this guy is doing in the presentation

http://www.youtube.com/watch?v=PUv66718DII

That would be awesome. Page Inspector is a cool idea but still it is a fancy way of browsing. Still need to press ctrl + shift + Enter (same behavior for browsers).

Whenever we are getting some error[the error types can be classified ] while debugging,VS should provision with a single button named as "Google it" or "Bing it" against the error..so that user can directly click the button and see the results against that error in search engine instead of going to the search engine and type/paste the error and press enter.It will save developer time and improve productivity.

ConfigurationManager (and/or WebConfigurationManager) could have a really cool dynamics implementation, whereby they returned singleton instances when doing something like WebConfigurationManager.ConnectionStrings.LocalSqlServer, which could return a type-specific instance of a SqlClient connection to my given connection string.