Here are some of my takeaways from the stream for those who didn't catch it, keep in mind I'm looking at this from the perspective of someone that's been doing m/kb -> controller emulation for a while so I am scrutinizing things most people probably won't care about:
1. The GUI for making configs is nice and flashy and shows what the controls are well, but it was taking them a long time to make fresh configs for each game. Switching around already-made bindings to other buttons should be easier. For example, when they wanted to switch around bindings for a game, they had to individually go into each binding and remake it. It would be way simpler if you could just drag the bindings around to whichever button, so if you downloaded a config that has all the buttons already made well but you just want to switch around the placements, you don't have to remake each one.
2. The Windows hotkey issue still remains. I asked Krejlooc to slow walk in MGSV (which would activate and hold 'ctrl') and hit start (esc) at the same time to see if it would trigger the windows start menu and have the game lose focus, and it indeed did. I was hoping Valve would have found a way to isolate inputs like this from Windows somehow, but I guess there is still time for that to be figured out.
3. The trackball inertia seems essential for having a good not too fast sensitivity while also being able to do quick turns in the heat of battle. Without it you would either have too fast sensitivity so that you don't have to reswipe so often, or too low and you would run out of surface area with your thumb while getting shot in the back.
4. The high resolution of the track pads led to some issues with higher sensitivity, where keeping the thumb in 'resting state' (ie: not trying to do any movement at all, just resting it stationary on the pad) led to some unintentional movement of the crosshair because of how the pad was still picking up micro-movements and the fast sensitivity it was set to. So if you really wanted to hold your crosshair completely still (like if sniping for example) and you use a higher sensitivity, it would probably be best to just remove your thumb from the pad all together so it isn't drifting around by a few pixels. This will be something to get used to.
5. Another issue encountered by other guy (sorry didn't catch your name) was that when pushing in the right trackpad as a button (say to click on menu items) that movement of the clicking in would register as trackpad input as well and move his cursor off the menu item he was intending to click. I think this is another issue related to a higher sensitivity, and lowering it would help so that the click in motion doesn't move the cursor so much. Then you would have to rely on the trackball inertia again so you aren't reswiping so often.
