It is also good at E fighting, diving, and stall fighting, I believe you're underestimating the aircraft.
"Good at e-fighting" does not mean being good at BnZ when you have airspeed - ANY plane can be good at that, the faster they are the better. That's nothing unique to the F4U-4.
Being good at E-fighting requires obtaining and retaining an energy advantage when starting from a co-energy state (i.e. same alt, both planes at cruising speed). In that light, in a co-E situation, it's a poor performer. All of the F4U's are mediocre at E fighting. The -4 does it best, but it's still lacking and will readily be beaten by the D9, TA-152, P-51, LA-7, K4, Ki-84, and many others in an even E-fight.
The -4 is a turnfighter that happens to have high
cruising speed and decent climb rate. This allows it to hang with E fighters initially, and then transition to a turn fight as entropy ensues the E states. However, it will still readily be beaten by most pure E fighters starting from a co-E state who know how to avoid the turn fight, as it cannot retain the E advantage.