Raise the connection timeout for slow connections as many sites don't show up at all.
On Windows 10 Mobile and Windows 10 on PC (using 3G networks), on limited bandwidth (64kbit/s), many websites will refuse to load at all, as Edge Closes the Connection as it times out. This worked fine with Opera on Windows 10, Internet Explorer on Windows Phone 8.1 and also works fine on Android's major browsers (Chrome, FF).
I suggest, the timeout should be raised on low-speed connections to allow the user to access websites at all. Adding a picture quality Setting would really not hurt either. I think this problem must be affecting many people who are on low-speed Internet.
This is really meant as a developer question, since it bothers me hearing that (not just my) websites cannot be accessed on Windows 10 Mobile due to the connection timing out, while it worked fine in IE.