MS is doing the right thing here and makes me as a Web dev and a WP user happy. Webkit, specifically mobile Safari, is pretty much the standard the mobile web works on these days. If IE and Safari both work the same, that saves valuable testing and development resources that could be used doing other things. As a web developer, that makes me happy. As a user, I want the sites that I visit to look good and work as expected.
Here's the other thing: I care about IE11 because it's half our IE traffic. I don't care much about WP (even though I use a WP phone) because it's 0.25% of our total traffic. I wouldn't have put that ugly hack in if it was a WP-only issue. Now I don't need to worry. If I can support mobile Safari, WP should work. This is good for devs and users.