Just to give more insight about the controller, a friend of mine who has a professionally biased opinion. The most he has said himself is that he liked it when he played an FPS with it, it's very mappable, and linked me a post he knew that would explain what I would ask him about how it works
Super Meat Boy and Spelunky VS Steam Controller
You can play Super Meat Boy at an expert level on it. :D
The track pads can have multiple mapped actions based on location. (Duno how many max possible). So there is no loss in buttons.
Dual-stick games, how often do you use all the front buttons? Xbox gots 2shoulder 2trigger, a total of 4 non-front buttons. Steam Controller has 6 because they have 2back buttons.
Plus the fact that they're making it so you could potentially design your own controller, so manufacturers can make different shaped ones if people want to have a more classic layout (but you can just plug in that 360 controller anyway since it's a computer).
Since it's a track pad, it'll be better for mouse based games than a controller. I assume there will be different modes of mouse movement behavior (moving based on location on pad*like a thumbstick* VS moving based on movement on pad*like a track pad*)
One thing to think of is we always used trackpads with the side of our thumbs or forefingers and they always sucked because how awkward it was to use it. On a controller using your thumbs is more natural and with that you can use it more accurately. I would assume it increases it's potential to come close to mouse use, at least almost on par with track-ball mice for gaming.
I wish this classic controller design would just die. it sucks.How is it a classic controller design? No one else would put all 4 font buttons and provide a larger area for the 2nd stick.
The reason the controller design hasn't changed is because the design they use now for the button count is efficient. A controller has to have grips, and the thumbs are the main tools we use for controllers (because fingers grip). Buttons are placed at comfortable grip points (shoulder, back), while the front controls are placed based on use and more comfortable position for that common use.
Before dual analog, the right area was used for buttons only, and no one has wanted to upset that because it works great. They added a 2nd set of shoulder buttons because they could not comfortably add them elsewhere. Same with pressing the thumbsticks down to get a button as well.
The Steam Controller upsets the standard by making it's "thumbsticks" take up more valuable real estate on the controller front, moved the front buttons to the middle because of their use in modern games, added another button to the back. If this was all it would be rather mediocre, but thankfully you can map the hell out of the track-pads for multiple functions to basically get a regular controller.