I agree, in the first few rounds you might want to hold off on loosing the fleet. The first few rounds are when you want to grab East Indies, New Guinee and if you can, the Phillipeans. By then, Japan should be good and mad at you and willing to throw anything they have at you to stop you from also grabbing Okinawa and starting to put “feet on the street” in Asia minor. (another tactic to force them to attack is to build an IC in New Guinee…it does Japan almost no good and it really makes them mad at you.)
By the time you have collected those islands, you should be concentrated enough with some DDs, some Trannies, a couple ACs and a BB (or two if you are feeling lucky) to stop a full scale Japanese assault. Sure, you can pretty much kiss your fleet good bye, but then so can Japan. Meanwhile, you now have an IC in New Guinee (if you built it) to pump out a couple subs and a couple trannies to annoy the ever living yoohoo outta Japan.
BTW, the whole goal of this game for me is to tick the other player off to the point they stop using rational thought.