No.  Not a ground up rewrite.  We need to keep many of the features and functionality that already exists. But everything in DNN today won't run on ASP.Net 5 (which is MVC only)  so we have to identify those parts that don't run and rebuild them.  We'll also take the time to revisit some outdated bits of the platform and either remove or update them using more modern approaches.

The point of this forum is to start having the conversations about what we should keep and what we shouldn't.  These conversations should be in the open rather than just limiting it to the MVP group or other private channels. The goal is to get participation from a much broader part of our community.

Technically you can say that ASP.Net 5 does include the full .Net stack, including support for Web Forms.  However, the core .Net stack is the only one that is Open Source, cross platform and which uses the new Nuget based deployment model.  Full stack .Net is there for Winforms, WPF, and ASP.Net backwards compatibility support, but in no way addresses many of the shortcomings of the current ASP.Net stack.

Microsoft recognizes that in order to truly address these issues, they needed to rebuild ASP.Net and the .Net stack.  If a DNN customer wants to take advantage of the benefits offered by the core CLR stack, then DNN has to make substantive changes to be able to run on the core .Net CLR.  So when we talk about DNN and ASP.Net 5, we are talking about the part of ASP.Net 5 that is truly new, not the part that is being carried along for backwards compatibility purposes.