[RC-Monster Mike]

Light duty cycles relative to what? I do agree with the premise of what you are saying and agree that there can be a tendency for slight overkill, but there is also fairly good reasoning behind this mantra. While average loads throughout the run may be fairly low(30 amps constant with 8s in a Baja is about 1 HP), the peak draws can be significant(5-6HP peaks have been logged on mine with a 1527 Neu motor). The high peaks yield fairly low efficiency for the short burst periods, which can generate some significant heat as they happen constantly(constant intermittent loads). The larger motors can simply dissipate the heat faster due to larger surface area, which can make them "seem" more efficient, but also can allow them to sustain better efficiency with the lower heat. When we are dealing with a couple to a few hundred dollars spent on a motor for the Baja, it means a larger motor, while perhaps not as "ideal" in some respects, is likely to run cooler and therefore less likely to fail. A larger motor is also theoretically less susceptible to thowing a rotor from the shaft when landing a jump or similar shock to the drive train, simply beacause there is more surface area at the magnet/shaft interface(I have thrown one rotor on my 1527 motor already).
I will likely continue to run the 1527 motor in mine, as I like the runtime, power and size, though I have added some heat sinks(2 Losi heat sinks fit perfectly and add a LOT more heat disipating surface area) and will add a fan if I need more cooling. If not for the heat sinking, I could easily overheat this motor and cause failure(and it is very close to a 2215 motor in overall size and power output), which is why people will tend to err on the side of "overkill". Likewise, if I ran back to back to back packs with this or a 2215 motor without cooling consideration, heat would likely win the battle - so a 2230 motor, while technically "overkill" for the task at hand, is likely to handle multiple packs on a hot summer day better than a smaller motor could.
Basically, I agree to a point, but also can respect and understand the reality of the situation and the reasoning behind it. sometimes bigger really is better(to a point). :)