I am surprised there wasn't a controller support before

For awhile there actually was some basic controller support, but it was never very good, and they ended up ripping it out so that at least community controller mappings could have free reign to do whatever they want. The basic problem has always been that the entire UI/UX is very mouse+keyboard focused; you don't want console users to have to pretend to control a mouse cursor, for instance, and there's always been far more keybinds than you'd be able to fit on a controller. The way to implement them properly is with a from-the-ground-up controller-focused UI/UX, which CSS didn't really have the internal drive to get done themselves. So, they basically ended up outsourcing it to the folks doing the console port, and then merged their changes back in for the forthcoming 1.1. It'll be interesting to see how it works, though I'm not a controller user myself.