Imo, The prob best way to use the heavy bombers should have been limiting the strikes against cities to only hit major industrial complex and vital industries (most of them were dispersed and out of reach anyway) and railway junctions. Other than that focus should have been military targets like airfields, ports, supply stores, troop concentrations etc.
The problems with this are manyfold:
US heavy bomber combat boxes were ideally about 2000 ft across for a 36 plane formation, and about 2500 ft across for a 54 plane formation. Mutual defense doctrine required these large formations in occupied airspace. They were often larger in practice, particularly when faced with heavy flak or high wind conditions. So, if you want large bomber formations, you're going to have to accept lower accuracy;
Major industrial complexes and vital industries
weren't dispersed or out of reach - at least not in Germany or Japan. They were typically located in and around the outskirts of major cities, quite often with high-density worker housing in the immediate areas. The same story goes for railway junctions, except that many of these were located in the residential hearts of major cities. Same thing for many airfields;
Precision really was not an option. 1944 medium altitude (15,000 ft) daylight missions had an average CEP of 825 ft to 1175 ft. At average altitudes of 23,000 to 27,000 ft, CEP for 1944 average just under 3000 ft. Blind-boming and missions with heavy cloud had CEPs of better than 5200 ft. The average 8th AF radial bombing error on German oil industry targets in 1944-1945 was
2.5 miles. Just
2.2% of bombs dropped fell within the boundaries of production facilities.
Here are the USSBS figures for September 1944 to December 1944 for "visual bombing with "good to fair visibility":
Percentage of bombs dropped within
1000ft 0.5mile 1 mile 3 miles 5 miles %eff
A 30.0 64.3 82.4 91.5 92.2 14
If you want to bomb nothing but military targets on the western front between 1942 and June 1944, then you're going to be fighting a bomber war similar to the one the RAF experienced in 1939-1940. You'll face a limited number of targets, of minimal to moderate strategic value, that are comparatively well protected. Due to the limited target choice, the Luftwaffe will generally know where you're attacking, and they'll be able to concentrate resources more effectively. Not a war I want to fight.
There was plenty the USAAF could do to improve its accuracy. From an old discussion on this topic, on another board, I made this list:
Use larger bombs,
Bomb from lower altitudes, 11,000-15,000 ft would have been necessary for sub 750ft CEPs
Bomb in smaller formations,
Increase intervals between bomb groups to reduce target occlusion
Reduce the width of combat boxes,
Switch to an all B-17 force, as they were more accurate bombing platforms than B-24
Increase the level of training for crews, particularly for pilots, bombardiers and navigatiors
Improve meteorological forecasting, particularly wind directions at targets
Never visually bomb through anything more than four tenths cloud,
Abandon blind bombing techniques
Introduce pathfinder aircraft
Reduce or eliminate use of fragmentation bombs and incendiaries
The 8th AF determined the four most significant factors in terms of accuracy were:
The cloud/visibility conditions above the target. This could affect accuracy by a factor of 10.
The number of bomb groups involved in the raid. A raid of three bomb groups was up to 40% more accurate than a raid of 10 or more groups
Bombing altitude.
The amount of flak over a target. Particularly heavy flak could halve bombing accuracy.
