I can nay remember the answer to this question so will ask.
Is it possible to duplicate the card database?
I ask for this reason. One thing that destroys RTS games which have a PvE and a PvP using the same materials is they can vary in mileage greatly depending on which you play.
If you make a PvP change in the name of balance, it can royally screw the card in PvE. So is it possible to duplicate the database then somehow make changes to the PvP database which would not affect the PvE database. I am sure it is not an easy change. But in the long run, may be the easiest way to bring balance changes that does unintentionally affect one or the other.