>>The G series didn't pick up until G6/AS or G-10/G-14. <<
The following is quoted from "An illustrated guide to World War II Fighters" Christopher Chant:
" The BF-109G was therefore planned from early 1941 as a development of the BF 109F with a considerably more powerful engine and, in reflection of the fact that both cruising flight and combat were taking place at increasingly high altitudes, a pressurized cockpit.....the pressurization system inevitably added to the weight of the basic airframe"
So what was happening was the 109s were being transformed by the necessity for more powerful aircraft. True the 109G6 then may have been less manueverable than the 109E or F but, it was faster and could handle combat better at hi altitude. There were few differences in the G variants other than the addition of pressurized cockpits, and cannon which were heavier and harder hitting eg. the 30 mm cannon versus the 20 mm, and variants of the DB 605 engines.
The drastic differences Kratzer and others speak of cannot be explained by your response AK Wulfe, and there may be a problem with the modeling of the G6 as compared to the G2 etc.
For example, according to what I have read, the G6 lacked the pressurized cockpit "as did all later G variants", and certain of them had the DB 603AM engine installed which could boost takeoff power from 1,475 hp to 1,800 hp and boost power available at 13,450 feet to 1,700 hp.
Heavier airframes had more of an impact on handling because of the added weight but, more powerful engines was the trade off.
There shouldn't be that drastic a difference between the models G2 and G6 other than the option to add increased cannon.
If any one of those guys who have complained are using the 30 mm cannon gondolas, they simply shouldn't use em, and ought to see a difference at alt in combat. If its low alt knife fighting they are referring to, then the 109G6 was not developed for that kind of fighting.