Edge will have to prove itself as a browser first. IE is inferior to all the others, currently. Edge, as "Spartan", has shown positive results in Microsoft's "lab tests" but they showed same results in the past so viewing such "reports" should be taken with a grain of salt.
It doesn't matter. Javascript is the default and what Google does with Dart does not matter unless everyone else is on board. This is a dumb, clickbait title.
I agree, and many home designs do that big window thing as if they have no neighbors, but the core idea is to think grand about one room and not just to have large windows.
You should always give rise to the thought that 80% of the web does not use Microsoft products. Which should tell you everything you need to know about why you don't need .NET.
Till then, stick with Firefox or Chrome.