Couldn't you just plug in a USB gamepad like a non-heathen?
When I spend an excess of 200 something dollars on my keyboard and mouse I'm not going to buy a gamepad. Besides, the game I play the most is Dota 2 anyways (for the last 12 years).
Silliness. The gamepad I use was something like $15 to $20. And it works perfectly. At that price, money is not an excuse, and this would completely fix your issue.