Which games are compatible with a Gamepad for PC?

Why don't more games for the PC support gamepad controls?

• For example, the PC version of Mass Effect 3 does not have a gamepad mode, and as a result 3rd party controller programs must be used-- and even then, assisted aiming is not supported, even though that was in the console versions. On the other hand, some games (like Borderlands) have a controller mode with assisted aiming for the PC. I've always thought it must be more work than not to make the PC version of a game not include the same quality of controller support as the console version. What informs these decisions?

• Answer:

  PC exclusive games are often designed to be controlled specifically with keyboard & mouse, and supporting gamepads would require development of alternative control scheme. Take Diablo 3, for example. It's obvious that simply mapping one stick to mouse movement wouldn't be comfortable to use — so, Blizzard should've spent additional time and resources (and with their quality bar, it would be quite an amount) to design, implement, test and then iterate it all over again. All of this — just for a small fraction of players who want to connect their gamepads? And then repeat for other forms of controllers? I don't think that any producer would do this for release (quite possibly in one of the patches though).