I'm a little nonplussed as to why you complain about the prominence/depth of the panel lines, then fill them in with thick black lines, making them stand out even more. This phenomenon didn't occur on the Spitfire, except where there were removable panels. The Spitfire was largely constructed with overlapping panels, which had primer and then top colours added, which filled the lines, and made it impossible for dirt to get through (or even stick.)
To be thoroughly realistic, many WWII models should not have engraved lines, but imagine the uproar if the manufacturers returned to raised panel lines, though, in 1/72 scale, the depth of the overlaps would be less than the thickness of tissue paper.i165.photobucket.com/.../IIA_zps2c48e88b.jpg