I've already lost any hope for some new Italian plane (looking other pastures for that), but i'll love to see some new addition in RAF, Japan, and URSS planeset.
There's little more (important) to add to the RAF planeset, but I think a must are the Beaufighter, the Wellington, The bleheinem (I have lost the spelling), the Gladiator, The swordfish, and last, but not least, the Meteor.
As for the URSS and Japan planeset there's a huge list.