Thanks for the feedback!
I was very serious when I referenced FluxBB 2. I was aware there would be onlookers who are not too keen on big JavaScript apps — if that's you, FluxBB 2 is exactly what you want (high quality pure Laravel open source forum software).
Flarum is all about taking advantage of modern web technologies — in a way that makes sense, of course. In the case of forums, they are highly interactive apps, so it absolutely makes sense to use JavaScript heavily. The best way to do that from a technical standpoint is to use a JavaScript framework like Ember. This means we have a nice separation of concerns (Ember is front-end, Laravel is back-end), and we can consume our own API, putting a mobile app or any third-party apps on the same tier as the official web app.
Your concerns about installation are understandable, but they're nulled by the fact that Flarum will come as a downloadable package with everything pre-compiled — you will literally be able to drag and drop a single .php script to your server, without any obscure dependencies (so it'll run on any shared host), and run it and everything will install. I don't think there will be any problem with adoption if it's that easy. (The current installation instructions are intended for devs!)