BnZs,
The fact that you don't care about bombs and rockets is precisely meaningless in this discussion, you are not the center of the universe. Any discussion of ENY must include all aspects of performance and capability. While I definitely agree that the P-51D gets additional use just because it is the P-51D, that alone cannot explain nearly twice the usage of of the runner up Spitfire Mk XVI, which also benefits from being a Spitfire like the P-51 benefits from being a Mustang. As an all around package the P-51D is very good and very effective in the game, to argue otherwise is absurd.
P-51D vs:
Typhoon: More ordnance, more maneuverable, more endurance, less firepower, slightly less acceleration
La-7: Much more ordnance, much greater range, easier to use guns, slower, less maneuverable, much less acceleration, less firepower
Fw190D-9: More ordnance, greater range, easier to use guns, more maneuverable, slower, less acceleration, slightly less firepower
Bf109K-4: More ordnance, greater range, much easier to use guns, better views, slower, much less acceleration, slightly less maneuverable, less firepower
F4U-1D: More range, better views, slightly better acceleration (if I recall correctly), faster, less maneuverable, not CV capable.
Yes, against them the P-51D has flaws, but the reverse is also true, against the P-51D they all have flaws as well.