the 20mm package was built in from the birth of the hellcat as an option. yes early test showed a jamming issue not fixed untill the f6f-5n. but it was an option non the less. that is documented fact. i would absolutly love to all the night fighters and actuall night time in game. its my understanding that there was night in ahI yet no night fighters.... why, i have no idea. everyone wants there own preferences brought to the game. this is my preference.
It was a factory design spec option and that's it. The F6F-5 was never delivered from the factory or deployed with the 20mm cannon weapons package. The same thing with wanting the 4 blade prop, it's not going to happen either because as others have already noted, the 4 bladed prop was only on two test aircraft. You asking for the 4 bladed prop would be like me asking for the P-38K.
Just because the design specs stated that it could mount 20mm cannons, doesn't always mean they were deployed that way. For example, the P-38 was designed to carry the 37mm Oldsmobile cannon but in reality it never had that cannon mounted. But using your argument with the Hellcat, then the P-38 should have the option of loading up a 37mm cannon instead of the 20mm Hispano it carried because after all the design specs said it could be done.
As for the night time we used to have, it wasn't 'true night' and most would just up the gamma to see in the dark. In order to make a night fighter viable, we would need a more accurate 'night time model' as well as modeling of the various airborne radar units that were used and a measure to prevent players from upping the gamma to see in the dark.
ack-ack