Anything else? Should FTB launcher for Windows Store support real java based MC or crippled PE version which is found in the store?
My answer as a dev: not going to use time for that.
Edit: Why? Use cases? Will it increase user base for ftb packs? That thing requires time to investigate tools & frameworks(will they even accept java based applications), changes in build environment(executable sign & uploads). Also there is questions like is it free, who can be uploader etc. => RoI? If positive when and why?