I still have trouble with accuracy and missing characters with the touch cover. I'll try the trick of resting my wrists to keep me in one place. I like the thin profile too much to move to the type cover. The touch cover is what makes the surface unique. If I need to do a lot of typing, I can always use a Bluetooth keyboard with raised keys. I just fold the touch cover over under the surface and use the Bluetooth keyboard when I really need to type a lot. (I am using a HP Touchpad Bluetooth keyboard.)
Similar position here. Been using the touch cover for a couple weeks now. Too many missed keystrokes for my liking, especially shift and control. And I'm not a noob typist either lol. But the thin profile as you mentioned is great for a cover. I probably will get a type cover soon though.
As for the mouse on the touch cover - it works okay. It's actually better than what I thought it was going to be. Two-finger scrolling (vertical and horizontal) is the only gesture that works, unfortunately (no swiping, charms, etc.). There is a slight pause after lifting your fingers from performing a scroll until you can move the mouse again. It's slightly annoying, but nothing extreme.
Another oddity I've had with the mouse is that sometimes when I first make contact with the track pad on the cover, it will mute/unmute the volume on my pro. It's weird. I can't reproduce the issue, it just happens randomly.