Add to that the browser is heavily integrated into the win32s code and you're in for a coding nightmare.
No, it isn't, and it never has been. You utterly fail to understand the 'integration' issue with IE.
IE itself can EASILY be removed from a system. Delete the EXE, done. Its been that way ALWAYS. Even during the court battles.
What you'll have a harder time doing is deleting the trident rendering engine, which MANY applications depend on because it provides a standard interface to providing a HTML renderer. File Explorer renders HTML in process ... using the Trident renderer. It doesn't have Trident code in it, it uses the trident ActiveX ... just like everything else. Just like many third party apps that wanted to include HTML, because MS made it drop dead easy to include an HTML renderer in an application.
The whole 'separate the browser from the OS' lawsuit was bullshit from the beginning. The IE ActiveX was fairly well documented, Netscape could have trivially made a compatible control that used the Netscrape engine, but the Netscape code was REALLY SHITTY, its a system issue they have which is why Firefox is crap to this day in so many ways.
They were never going to be able to develop for changes as fast as competing browsers with that model and they knew it.
Funny, you've not been paying attention recently have you, they've been doing pretty good. Of course, unlike other browsers who aren't integrated into everything on the system, they do have to consider that they might break everything on the system when doing code changes, unlike say ... chrome or firefox who just tell you to go fuck yourself and upgrade everything that uses them, regardless of the fact that you might not have the ability or source code to do so ... oh what? You're not using entirely open source software, well then you should definitely go fuck yourself, right?
Just for reference, Apple does essentially the same thing with WebKit on OS X/iOS
As long as they stay dedicated to working with web standards
You do realize that IE 11 more closely adheres to W3C standards that any other rendering engine, right?
Microsoft is a monopoly abusing bunch of pricks who need to be taken out back and shot, but pretty much everything in your post is wrong and easy to verify that its wrong.