I've been building in MVC3/4 for the last few years so have quite a bit of experience with how MS has been evolving in this space. From "BundleTransformers" through "Web Essentials" and now suddely all the way to GULP
I started building a weekend and evenings project in EF7+MVC6 at Beta6 and have suffered through breaking changes in beta7 & 8 but each stage of the way I've enjoyed myself.
Some of the things that I have recently struggled with is getting the project working on linux VMs and docker.
While I can get boilerplate projects working, this "bigger" project struggles to compile on docker.
Part of it may be my own fault since I've split the solution into multiple projects ("WEB", "API", "MODEL") where MVC6 seems to have a paradigm of keeping everything in the same project, but it does seem to work OK on a windows 10 host (I keep wanting to test it on azure but that's another story)
There isn't any clear path as of yet from "building something that runs locally in VS" to getting it hosted in a "massively scalable cloud of containers"
I'm exploring docker and kubernetes at the moment - but progress is slow :)
Additionally - in terms of development - I'd like to see some more scaffolding, like I see with (for example) strongloop/loopback in node.js I'm finding that my API breaks down in .NET when I try and use an EF entity around since we get into circular JSON references.
Anyways, I'm starting to get off on a tangent. I really do like what I see in .NET5 though feel there are some pains in places. Specifically around containerizing & rapid application development.