I've just finished the arduous task of submitting 775 QSLs for various DXCC awards and one change in the Submission feature would have made the job MUCH easier: Would it be possible for the Submission sort to be by Prefix (in DX4WIN language, that's DXCC Entity) order, rather than by Callsign? As an example, the card for 3E1DX would appear under HP Panama, rather than under 3E1.
For those of us who file cards in country order, this change would make pulling those cards for DXCC submissions more efficient (if still not pleasurable!). 73, Dave, W2PK