Sony are poised to add system level support for their DualShock 3 controllers to their Xperia-branded smartphones. A user would be able to wirelessly connect their controllers without root or hugely complicated setup procedures, using just a USB OTG cable for the initial setup.
All you would need to do is plug the controller into your Xperia device's USB port, turn it on, enter the device settings and then just enable the controller. Once there's some talk between the device and the PC, you'll need to unplug the controller and then you'll have the ability to use it through Bluetooth.
At the moment there's no news on whether this will jump across to non-Xperia-branded smartphones, but I'm sure it'll just be time for now. Games that support a controller are obviously the way to go, but this isn't a big problem.