You can do anything in Superbike. And Ed Key still runs a carbed SV rather than an FI SV. The FI bikes are a little better not just because of the FI, but they have more processing on the ignition, changes in geometry, etc. Might even have better brakes, less weight, etc.
You got there while I was still writing, Ben,
My feeling here is that FI is great in you're running a stock or mildly modified motor. But as compression and cam duration increases, carbs become more attractive. On every FI motor, at some point just adding injector pulse width will not get you the fueling you need. As RPM increases, so does the importance of injector phasing. If you're not working with a fully tunable ECU (like Nemisis, Ultimap, or the Jap-race ecu's)... you're just plain not going to get there. Even if you are running an adjustable ecu... good luck finding someone who can tune it for a reasonable price.
Because of electrical demands of FI, you carry around a full charging system and need a larger battery to bridge the gap between peak usage and charging capability. Being able to run total loss is worth a lot of weight loss... when you figure that the wiring harness alone for FI bikes weighs about 3lbs, plus the fuel pump and filter, plus the charging rotor, stator, and rectifier, plus the YTX5L-BS battery you can run instead of a YTX12... its about 20lbs. (3-4lbs of which is spinning weight)
I'm also not sure if a faster ecu with "better" ignition timing is really very good for roadracing. If you look at an FI ecu's ignition table the advance gets pretty crazy at part throttle , roll on. Instantaneous response is not exactly what I want when I'm already near the limit of traction... especially in wet racing conditions. Of course you can tune that out... but now you have one more thing to jack with.
Flatsides are still cool and get the best results for tuners of common ability.