I may be biased here since I make fuel injectors, but how are you arriving at your WOT conclusion? Fuel injectors have a predictable, linear response across the entire power band and do not starve the engine for air, which is the only other component you need.
If we are talking about throttle body injection without timing control, then yes I'd be inclined to agree but multi-port FI with timing control and O2 sensor closed loop control is a solid platform for any engine with respect to drivability.
More complicated, yes, but not overly so.
Decades of experience racing against all comers. Pro Stock was forced to switch to EFI (formerly running with twin Dominators for 2100 to 2900 cfm on an independent runner manifold) because Chevrolet threatened to pull it's sponsorship if they didn't. Took them three years of testing and tuning to get back to the same power level as before (3 hp per cube out of a normally aspirated BBC).
I am a mechanical engineer that has been self taught in automotive engineering (since there are only three schools of automotive engineering in the US). Read texts on carburetion, exhaust flow suspension: all out of date now, I'm sure, but I understand the basics. This includes EFI as I have not dismissed it out of hand but studied it's Pros and Cons.
If I where to build a new car with LS power I would retain EFI only modifying it for a higher duty cycle as I would be punching the motor out to maximum displacement with freer flowing aftermarket heads (I can't help myself as I am as addicted to power as any B-film 1950 SciFi villain). I would not be retaining the factory computer, or displacement on demand, or variable valve timing (due to it's physical limitations not because it isn't a good idea). I await an age of push rod independence with direct injection and a slide valve block with a flat head.