Microsoft have created a site where you can vote for your most wanted Internet Explorer features. The IE team may use this feedback to consider which features to prioritise. I thought I'd point out features relevant to Construct 2 so you can add your votes if you want to see them supported.
Note you get 25 votes per account and you can use 1, 2 or 3 votes on each item. So you can add extra weight to your most preferred features.
My personal #1 request: Ogg Vorbis and Opus audio formats support - dual encoding is a big pain for everyone, and IE supporting Ogg Vorbis (or even Opus) would be a good step towards fixing that. Please add votes for this!
Other features relevant to C2:
Frequent updates development cycle
WebRTC support (for multiplayer to work in IE)
Web MIDI API (would enable a MIDI plugin in C2)
a[download] attribute (so 'invoke download' can work in IE)
Web Speech API (input) (for speech recognition to work in IE)
Web Speech API (synthesis) (for speech synthesis to work in IE)
Battery status API (so the Browser object's battery features work in IE)
Vibration API (so the Browser object's 'Vibrate' action can work in IE - useful for physical feedback on mobile)
WebGL 2.0 (enable some useful extra rendering features in WebGL mode)
Note some features like the Web Audio API are already stated as 'In development' on status.modern.ie. There's no need to vote on things listed there as already in development, hopefully they will turn up soon anyway.