Force Touch is pretty cool - I have it on my watch, and I have found myself force-pressing things on my phone to no avail.
The problem is if it's scattered around to do very different things in different places. Some buttons will be pressure-sensitive, but you won't know which ones just by looking. Launching an app could do different things depending on how much pressure you use to launch it. I don't like it - there doesn't seem to be a unifying theme or concept I can use even to guess if something may be pressure-sensitive or not.
We kind of have this problem on the Mac already with the alt button. If you hold it down, sometimes it'll change buttons and menus and expose some incredibly useful things. But you don't know what's there unless you try it and browse the menus, then you'll forget where things are because you can't see them, etc. Discoverability is a big problem for these kind of hidden menus and actions.
I guess that what Apple is doing is basically giving developers a raw hardware feature without much idea how to integrate it in to the OS. Then they're going to see what we do with it, then they're going to use that as "inspiration". That's kind of lazy from Apple's side.