2. WebGL and even Canvas are significantly more performant. I realize that's comparing apples and oranges... Still, if I had a choice for any data visualization project today I'd use WebGL rendering, or ThreeJS etc.
It did seem rather unfair of the article to bash Microsoft/IE so much over SVG support, when actually today the performance and sometimes rendering quality in IE is dramatically better than the likes of Chrome and Firefox.
But in any case, you're right, performance is a significant real world concern if you're using SVG for anything beyond very simple diagrams or line art.