Where do you get the idea that the P-38 had poor power loading?
Guess again.
Look more closely at the chart above. The P-38 has BETTER power loading in that chart. Better than the P-47, better than the P-51, better than the F4U (except the F4U-4), and better than the F6F. That does not even take into account the P-38L engines were rated at 1750HP in WEP (notice you never see published WEP ratings for the P-38L, EXCEPT in Lockheed documents, you ONLY see METO, which by the way is the same rating as WEP for a P-38J).
Drag? Sorry dimwit, but there is not an extreme difference between 0.22 and 0.28. Now, the P-51 DID have a decided advantage, IF that 0.17 is factual.
No, the p-38 was not the slowest accelerating U.S. fighter, not by a long shot. And it enjoyed a climb advantage over the P-51, the P-47, the F4U, and the F6F at most altitudes. With regards to U.S. fighters deployed to Europe, the P-38 was the fastest accelerating fighter from cruise to about 375 MPH.
Only the P-38 and the P-47 could maintain sea level power up to anything near 30K feet. The rest were sucking wind. Even with the supercharger in high gear, the P-51 was still lagging behind in power.
Properly operated, the P-38J and L had a greater combat radius than any other U.S. fighter.
The P-38 did suffer from maneuverability restrictions and dive restrictions above 25K before the installation of the dive flaps.
By the way, if you knew anything at all, you'd know that comparing wingload by area and weight alone is a total joke. That ASSUMES (ASS being the key word in your case) that the wings share the exact same airfoil type and profile, and they most certainly DO NOT. The P-38 had a broad chord high aspect ratio wing. It provides significantly more lift per square inch of area than the wings of other fighters. The airfoil profile selected for the P-38 is the reason it reaches compression at a lower speed than other fighters. Because the air flows faster and provides more lift. Kelly Johnson wanted to use a thinner profile, but the requirements of range, lift, and climb rate (the P-38 was originally designed specifically to intercept bombers) set forth in the USAAF specifications required the high aspect ratio profile that was used.
And the definitive work regarding the P-38 is "The Lockheed P-38 Lightning", by Warren Bodie. Bodie is regarded as one of the top historians in the World War II aviation field, and is a retired Lockheed engineer. It has all the facts YOU will NEVER want to read, backed up by USAAF documments, Allison documents, and Lockheed documents. It has been recognized by Johnson, Levier, Meyer, Mattern, Kelsey, and a laundry list of others, as the most accurate work on the P-38, period.