A) Calling on the standards card for a Microsoft product is hilarious. When Webkit has literally the browsing market - especially the mobile browsing market - anything else is irrelevant.
B) Mobile IE performs like hot garbage compared to Mobile Safari. I will say nothing about Chrome (beta) here.
I know it is. That doesn't make the point any less valid. All I said was that it shouldn't matter, not that it doesn't matter. Also, even though it is not the same situation, I'm sure people said the same about IE back then. WebKit is as much as a web standard as IE6 was back then.
As for speed, I have no experience with a new flagship Lumia, but I doubt that speed is an issue outside of benchmarks.
Here's a speed comparison between the 1520 and iPhone 6 Plus.
https://m.youtube.com/watch?v=h9UX3foc8Gw
I stopped after 5 minutes, because it looked pretty even. The pages look good as well. Maybe it gets much worse later on, I don't know.
I'm not sure how you'd compare a Snapdragon 400 device like the 635 or 830 with an iPhone, though. Perhaps with Safari on an iPhone 4S? I have no idea how comparable the SoCs are.
Either way, I guess there's a good reason why Microsoft is dropping the IE name.