I would suggest using software like Joy2Key as you can map the mouse cursor to a thumbstick. It is a bit awkward using mouse with a thumbstick, but it does work ok. I once tested out playing Soldat with my Madcatz dual-analog controller. For running and jumping, it was excellent, but for aiming - since in soldat you have to be able to aim and make a kill in 0.2 secs, it was too slow. But I think for KAG it would be just fine. Archers are the only ones who aim, but don't need to aim quickly. For builders, you could slow down the cursor, so that it's easy to aim your square around when building/digging.