I'd like to see BB's in the game, with realistic damage modeling. They might be considered to be the Tiger tanks of the sea, it's a major project to sink one. Musashi took 19 bomb hits and 17 torpedo hits before sinking, Ive read.
I usually get around 5 perks for sinking a carrier (while dying); I'd like to see those perks adjusted upward, with similar perks for a BB. After all, fleet carrier losses had major impacts on the Pacific war, e.g. Midway (including the loss of the carriers' planes and pilots) and BB and CV availability and losses had major impacts in the Atlantic theater, at least until Germany got wiped from the board and Italy changed sides.