I feel like this was addressed a bit in the linked blog post: the support is getting better and it's now "in the family" as opposed to a primarily community and research-supported "toy".

I'm looking for the nearing releases where F# starts to share much more of the same Roslyn platform that C# and VB have been using for a while now. That should be some very interesting tooling to have at F#'s disposal.

C# is always going to be the flagship for the same reason that C/C++/Java/et al are still some of the most common programming languages in the world. That doesn't mean that we can't expect good things from F#, though.