I hope there will still be guys to play with when the changes get made.
You could always do something kind of generic:
If their listed position is C, make them 100% at C & PF
If their listed position is PG, make them 100% at PG & SG
If it's SG and they're above 6'5", make them 100% at SG & SF.
If below, make them 100% SG & PG.
If it's a SF and they're above 6'8", make 'em 100% at SF & PF.
If they're below, 100% SG & SF.
If it's a PF and they're above 6'10", make them 100% at PF & C.
below, 100% at SF & PF.
Then make a couple of exceptions (probably less than 20 players) that play 3 or more positions.... Magic Johnson, Oscar Robertson, Lebron James, Michael Jordan (88-89 season), Rasheed Wallace, Kevin Garnett...
Bam. Much more flexible PE. Some players will ***** and moan about it, but there always will be those doing it. A less exclusive player-set is much better than the current one, and it should be relatively easy to set the parameters.