Pinch-to-zoom is already enabled in playback mode (actually, it seems to be the only way to zoom in on the photo - I find it a little irritating and would definitely like to be able to double-tap the screen to 100% zoom). I don't think I've found pinch being used anywhere else. You could possibly use it to perform the 5x or 10x zoom, but you'd have difficulty doing it without stuffing up your current af-point.
The android app (
https://play.google.com/store/apps/details?id=eu.chainfire.remoterelease) does not work for the eos-m (I presume it uses the tethering API).
Changing Av/Tv/ISO/exposure-comp/af-point using touch-only is very easy already. Altering the audio-recording level is a bit finnicky (or is this something the video guys set once and never really touch again?) and also it would be nice to "touch to focus" (like on a smartphone) - at the moment it's either "touch to set af point" (you then need to hit the shutter to af of course) or "touch to focus and take a photo" - nothing in-between.
Would be nice to have a way to lock/unlock the af-point to its current position as it's very very easy to touch the screen accidentally and muck up your selected point. A good option here would be if the video-record button could toggle it.... that button is currently unused in green-box or stills mode.