An Indoor or five-a-side version should be easy for Konami to program (just add a new, small 'Stadium').
It would reward close control: short dribbling, passing and accurate shooting into smaller goals - which would be good for a player's skill in normal games. (I put gaols first, must be thinking of certain top English players)
It could be played among your own players in Master League and offered as a PES Shop option to add as a an Exhibition stadium - which beats the normal Training Ground.
I agree with those saying vary the referee's strictness and willingness to book players. And mayber stricter in WEFA matches and Cup semi's or finals than normal domestic league games? (Can I get Classic Gazza to cry?)
Make the Classic Teams specific to particular tournaments not having Gazza play in the same team as Charlton - e.g. Brazil '58, '70 and '82. England '66 and '90. France Euro '80, Holland '74-78, and Euro '88. Argentina '78 and '86. Italy '82 I guess?
Or what about classic club teams? Madrid of the 50's, Man Utds Busby Babes or European Champions of '68. Liverpool of the late 70's or early 80's. 70's Ajax etc etc.
Can we have the 'benefit of the doubt' in offsides going to attacking team, i.e. if you can't see daylight between attacker and last defender, the play goes on. And players moving backward should be counted as inactive, unless the ball actually comes to them.
Oh, and players about to make runs into space point to where they want a 'through' ball - if the player on the ball spots them and has the passing skill he'll be able to get the right weight on the pass, others will over or under hit the ball which is what normally happens now.
Thus, 'playmakers' would be able to 'pull the strings' of attack from midfield. And add another Foward position for the playmakers up front, like Totti and Bergkamp, who tend to drop deep into 'the hole' between CF and OMF.