Please notice that I am separating out the capabilities of the aircraft from the actual usage. In 1940 the Germans had no need of a different aircraft or airframe. The "F" version continued the 109s position as one of the best, but with a different tail ( no supporting struts) and a modified wing and forward fuselage/cowl there were some significant changes. For 1941 there is still no other challenger than the Spitfire (except maybe the Zero). At some point in 1942 things start to change. Spitfire weapon load has gotten much heavier starting in 1941, American planes, while not in theater yet are rolling of the lines with heavy armament if not sparkling performance. (P-40E&Fs) Early P-47s. P-38s. FW 190s for the Germans also show the future. Typhoons also show up, badly flawed, but showing the trend.
I agree in 1942 change of things. But in opinion, Allied designs, including Soviet, were very poor in early war with many flaws... all these well known.. negaive G, lack of cannon, too weak engines, poor designs with old fashioned airframes.. no drop tank.. production failures etc. In 1942 designs got better, same class as German or Japanese, flaws eliminated.
This and earlier you showed weapons got much heavier in P-47, Spitfire. I ask: and? Weight of guns is not measure of weapon effectiveity. Was Type V Hispano worse than Type II? It was lighter.. but fired more. Was Soviet B-20 cannon worse than Swak? It was lighter for certain.. so you comparison analagou would show weapon was bad in comparison because it was, gun and ammo, lighter.
Sorry to say, this is flaw in logic. Measure of firepower is weight of own shots in enemy plane, not weight of shots and gun in own plane.
Accuracy, concentration fire, shell power, number of shell, ammunition available - these count. Weight of guns - do not help. Less weight, the better. Also trends. Trends were centralised guns - Soviet, French design too - increasing armament - 109G had increased armamanet, three cannons, two machineguns. Surely there was no lack of firepower with 3 MG 151/20. And before you say - decreased manouverabiliy! Why, add weight did not decrease manouverability in Spitfire? Typhoon? FW 190? Add armament, add weight. Decrease manover. All planes. Was new trend plane Typhoon more heavily armed than 5 point Messer? No. Was it more manouverable - no, it was less. Was new trend plane 190 more heavily armed than 5 point Messer? No. Was it more manouverable? Again, no. NIIVVS tests show similar.
I ask: then...?
You also forget why there is more guns in these planes. Because guns in wings. Wings only can have symmetric guns, in each wing. And why in wings.. well... can you put a gun in Merlin - no. Can you put gun a Sabre - no. Can you put in radial engine (any) - no.
By 1943 the 109 is no longer in the front rank as a fighter bomber. It's air to air armament in the early "G"s leaves a lot to be desired. A single 20mm and two 7.9mm mgs is just not world class. It can be fought effectively by good pilots but it is not the armament anybody designing a new fighter would pick. actual speed, climb and air to air combat performance is still very good but range is little better than the 1940 "E". the lower drag and more efficient engine help but with no change in fuel capacity the ability to "project" power is lacking. Withe Luftwaffe going over to the defensive this is less important to the Germans but is another strike against the 109 for considering it world class.
Soviet considered 109G world class. Very fast, very good climber, 5 pointer Messer heavy hitter too. You forgot 5 pointer - and all 109G can be five pointer.
Regarding range - range was much better than 109E. 109E was very poor. Already 109F - very good. G - same. K - probably same or better. See:
http://www.beim-zeugmeister.de/zeugmeister/index.php?id=33&L=1'
1600 km range, 5 1/4 hours in air. Sufficient for any task. Why add fuel capacity (weight), if not requested by official? If operation not require it? Did German had to escort B-17s from London to Berlin? Fly in Paicific carrier battles? Name task it was insufficent..
The G-6 bring the 13mm cowl guns which, while nice, are a day late and dollar short as far as firepower goes. Newer DB 605 engines keep flight performance up which keeps the 109 useful as a point defense interceptor. Provision of the 30mm MK 108 cannon helps firepower at the cost of combat duration. 6 seconds of firing time is rather short. The British have been doing better than that since 1941.
I disagree. British armament was technological backward. Look at armament - guns in wings, 4-5 meters apart. Concentration fire - poor. Soviet had Spitfires, considered weapons badly located. All Soviet aircraft had weapons concentrated in nose. Also 109, P-38 etc. All post war aircraft had weapons concentrated in fusealge. Wing armament - simply backward. Very much weight added for much less effective increase in practical firepower. Reason: wing installation less rigid. Less ammunition in wing. Two guns, but two guns rarely hit target at same time. Two guns weight for one guns firepower.
And 7.7 mm machinegun - useless - until 1944. Even in 1945 in many planes. You pick out things and forget complex picture - yes 6 secs fire for MK 108. And? What happens to target after 1 seconds? MK 108 is one hit gun. Fighters literally fall to pieces from hit.. So why did Germans choose to use it in so many fighters - previous had 20 mm with 15 seconds fire (200 round). British had Hispano with 12 seconds fire (120 round). German still saw MK 108 as improvement in big picture.
The Late "G"s and "K-4" get even more engine power but darn little else.
They are fast with excellent climb and good agility but lacking in both flight endurance ( again, less important to the Germans but saying the Germans didn't need a little more is making excuses) and combat power, a single 30mm cannon with 60 rounds and two 13 mm pea shooters (the least powerful 12.7-13mm mgs used by anybody). Bombing ability is no better than a Curtiss P-40C.
First part - endurance - you have wrong facts. Late 109G and Konrad had good endurance. For example why need more than 5 hours endurance. British papers above show. 13 mm gun is weak compared to others, yes, agree. Also very light. You forget however concept - 7.62 mm guns were too weak for armor. 13 mm version was only meant to be sufficient against armor. It was. I do not think more was needed. Nor that two more powerful 12.7 mm would be improvement - perhaps soviet UBS. Same weight, improved characteristics. Perhaps synchronized installation not very good - German gun was electric, no loss. But even firepower would be similiar - all 12-13 mm guns are just making little holes. Their advantage is better balistic and reliable penetration of armor compared to 7.62mm gun.
However, I do not see what is major problem. Armament was similiar to major Soviet fighter aircraft, Jakovlev 9 and 3 - actually these carried less ammunition, and range was less. Armament in Western aircraft? Spitfire already noted obsolate arrangement, little ammo, ammo is inferior quality, 7.7mm guns completely obsolate. Typhoon line is heavy, but then again, there is possibility for 5 pointer configuration.. American? P-51 is simply week, at best, equal to 109 with base armament, much inferior with 5 pointer. P-47 is aduquate, but 8 12.7mm guns at weight of 8 cannon is simply stupid. Again, both obsolate arrangement: this means you carry 6 or 8 guns, fire 6 or 8 guns, and hit with maybe 3 or four. Concentrated weapons: you carry 3 guns and hit with 3 guns - and one of three is a cannon. And you have more ammunition for each gun. Actually, only plane that comes close is P-38 fighter. Consider ammo is very similiar, one cannon, four MG with lower cyclical rate. Very much praised by pilots. Concentration firepower. This was future, plane itself is more like interesting concept. Not bad at all, but not economic.
Bombing you are right. 109 is avarage 250-500 kg, like Spitfire. I guess more, like twice possible but there was also 190 (and Typhoon), better suited. So why develop..? Solution is already for problem. Which airframe could save all problem - none I believe.. not possible.