We’ve had the same issues, but now we have a fairly smooth running windows phone and windows 8 ionic app. The most important fixes were:
1: Loading fonts from local filesystem don’t work, but loading from a CDN does: [WP8] Ionicons not display
2: Set overflow-scroll="true" on your <ion-content> to disable Ionic’s virtual scrolling (which is clearly not designed to work with IE) and use IE’s native webscrolling
3: Stick with beta6 because the latest version enables page-animations, which are clearly not designed with IE support in mind. Or maybe you can use beta8 with that animation disabled, but I haven’t tried that.
Good luck and let me know if you run into any other problems, because I’ve probably had the same problem 