Valve now offers a June update on their Steam Controller, discussing how developers are better supporting it in new releases, and discussing recent improvements to how the controllers work. They say they've sold more than a half-million of them, and they are making good use of all the data these are producing. They conclude with an idea of where they are going next:

Coming soon: Even more configuration power
You will soon be able to use Activators to assign actions to press-and-hold, double click, toggle and more. For example, in DOOM you can cycle through all weapons by pressing a button or double tap it to bring up your BFG.

We'll continue to add features and functionality going forward, so be sure to keep giving us feedback on what would make the Steam Controller even better.