Mechwarrior needs joystick support. I've played every iteration of the game and it's always a much better experience with good stick support.
That being said, make sure the joystick support isn't an afterthought. A lot of games out there these days really cut corners when coding their device support.
The game needs to support multiple sticks, allowing people with more complicated (stick rudder and throttle) setups to use their hardware.
If/When you do this, please don't botch it like some other studios.
Some games have bad input device enumeration. For instance,777 Studios and Maddox Games titles both assign joystick IDs alphabetically (technically numerically since the Vendor & Product ID are in hex) based on VendorID&ProductID. This causes issues when controllers are added/removed/changed on the system, causing users to have to remap their controls from scratch and even leading to crash conditions in a few games.
There are 2 better ways that work better:
Assign controls on a per device basis, keeping devices separate by way of the GUID (FSX and Eagle Dynamics titles do this)
OR
On game launch check each active devices JoystickID binary value in the registry key and use that value to assign ID1-IDn to each attached device. (a few games and the FSUIPC addon for FSX do this)
Both of these methods allow users to do things like swap one joystick for another without ruining the controls they've mapped to other directinput devices such as throttles and rudder pedals.
The Joystick ID and GUID values are stored here:
Windows Vista/7
HKEY_CURRENT_USER\System\CurrentControlSet\Control\MediaProperties\PrivateProperties\DirectInput\[i][Vendor & Product ID for each DirectInput controller][/i]\Calibration\0
Windows XP
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\MediaProperties\PrivateProperties\DirectInput\[Vendor & Product ID for each DirectInput controller]\Calibration\0