Yeah, I tend to get carried away and then wind up not building anything because it has become too complex or I think of another "even better" way to do it. What you have is elegant in its simplicity and function. I would probably add a PIC circuit with various inputs and a display to read voltage, current, power, and RPM, and perhaps temperature and air pressure. It would function as a datalogger and send the information over a Bluetooth serial connection to the computer for analysis.
Using resistors is better than incandescent lamps because their resistance stays constant, whereas lamps can have about ten times lower resistance when cold than they do when glowing brightly. That can also make them present a tough load if connected during engine start-up. With a good flywheel they'll probably reach incandescence quickly enough to avoid slowing down the engine very much.