It would be great if we had control over defensive substitutions and player rest on a player-by-player basis..  we can do this for pitchers on the Player Settings page, but switching over to position guys gives us the checkboxes on the left and a bunch of pitcher settings.. use the additional real estate on the right for drop boxes for "Inning Available for DefRep" and "Inning Available for Rest" and even "Inning Available for PH"..

or perhaps, along the same vein, a dropbox for minimum # of PAs before a guy is yanked for a better glove..  something "more realistic" than a wave of better leather taking the field in the 8th or 9th inning..

.............a la move cody ross to LF after pat burrell Ks for the 3rd time, and bring nate schierholtz into RF..