This is an interesting look into the new technologies coming from the asp.net team. So far things seems to be an improvement on the older framework.
Its nice to see Microsoft branching out to other platforms to give people options, although the prejudice from Linux/Mac users to use Microsoft software I think is quite a high barrier to break into.
There's also some great performance updates coming with the next version as well as a just in time compiler for your server. Personally I think i'll be sticking with the performance benefit of complied dlls over this as I'm not too fussed on my builds taking awhile.
The asp.net team always brings out some excellent frameworks to add to .net and it looks like they are not going to disappoint with the next frameworks.
Microsoft feels that System.Web needs to be removed because it is actually quite expensive. A typical HttpContext object graph can consume 30K of memory per request. When working with small JSON-style requests this represents a disproportionately high cost. With MVC 6 new design, the pre-request overhead drops to roughly 2K. Included in MVC 6 is Web API and Web Pages, allowing Microsoft to remove a lot of the overlap between the three frameworks. One result of this change means that MVC will be self-hosting just like Web API 2 and SignalR 2.