The fact you can intermingle .net core and .net framework libs and VS will handle the interchange for you now seems like a really nice addition. I haven't had much chance to play with Core but knowing they've simplified things has me anxious to give it a try.
It does make it much easier to get going. Most of the packages you expect to be able to use are there. This only becomes an issue if you want to run cross platform. Once nice thing they added recently is that they issue warnings if some of those packages depend on Framework, which helps.
Right, would make actual cross platform harder, but potentially transitioning a .NET Framework app to Core would be easier as you could do it in phases with less dev effort. Something my work should probably look at at some point since we're currently a Framework shop (still using 4.5.2 I believe).