The WASD uses "OEM profile" or "filco profile" which is taller than SP or cherry.
You can probably get a set of cherry PBT or POM for pretty cheap. (Either from a cherry G81 keyboard on ebay, or someone who replaced his cherry keycaps with doubleshots) Cherry PBT and POM are both really excellent, and low profile.
I'm a little tired, so I'm not seeing how keycaps will reduce effort, but you may want to consider O-rings, as they will reduce the key travel distance. Also, learning to not prett the keys fully should speed up your typing somewhat, and greatly reduce effort.