I have an idea for BM
I think the kamikaze rules of G40 should be considered
Kamikazes as far as I know were involved in fleet battles where Japan always had a SURFACE FLEET presence
With the addition of marines, kamikazes severely limit the usefulness of American marines on cruisers
I would like to see the kamikaze rule changed to be that they can only be used when Japan has a surface warship defending in the zone. Then uncontested amphibious landings by the marines could be done.
Keep in mind that originally the kamikazes required a certain island to be taken by the Allies before they could be used, and then they were boosted significantly by the removal of that requirement (also simplified the game)
I realize this also keeps Japan from being able to stop ALL BOMBARDMENT on any given amphibious assault (and there could be a big one) unless they have a destroyer in the zone, but I think this is OK. You could always re-think how many kamikazes Japan starts the game with, too.