The Japanese doctrine certainly did contribute to Japanese casualties here: I discuss that a bit here. However, a far greater reason had to do with the sheer firepower imbalance between Japan and the US.

Your typical US infantry division could call upon something along the lines of three-to-four times the artillery firepower that a Japanese division could. In addition, the division itself had access to far more heavy weapons, far more squad support weapons, better logistics overall, to say nothing of naval support, air support, armored support, combat engineers, demolitions, superior intelligence, superior communications, and so on. Even during the initial Japanese successes in the Pacific, the Japanese landing troops were often deprived of naval support, as the Navy, in addition to having a fierce rivalry with the Army, also was under strict orders to conserve ammunition and fuel. The result was that unsupported Japanese troops often took far heavier casualties than an Allied landing force, which would benefit from naval and air bombardment.

Japanese logistics were also an absolute travesty. Tameichi Hara discusses for instance the operation on Guadalcanal, where a Japanese brigade dispatched to kick out the US Marine division already on Guadalcanal (which already says something about the poor Japanese strategy involved) was to be landed on Guadalcanal by night-time destroyer runs-the "Tokyo Express." Aside from the fact that this was a substantially suboptimal way to deliver supplies or utilize destroyers (as destroyers were forced to take off some of their armament to carry troops, reducing their combat effectiveness), the Japanese troops that landed were unable to bring any of their heavy armament with them. Unsurprisingly, they were cut to pieces by entrenched, heavily armed Marines. Japanese resupply also was a travesty-delivered by dropping off barrels in the ocean in the hopes that the current would carry them to the Japanese part of the island, something like 10% of the supplies actually were received by the Japanese troops, to say nothing of the amount that was captured by the Americans. The Japanese navy did conduct some bombardments on the island at night, but this paled in comparison to the constant air superiority of the "Cactus Air Force" that the US Marines were able to rely on, especially after the repair of Henderson Field.

Japanese air casualties were primarily due to several questionable design and tactical decisions by the Japanese army and navy air commands. /u/Kieslowskifan goes into detail here.

Presumably you mean their ground forces?