I've given a bit of thought to the cross-generation metagame. I don't want to start a thread until it looks technically possible, otherwise it's just vapourware.
I think the mechanics could be hybridised. A few examples:
The single special stat in RBY could perhaps be implemented as an ability, that would transfer boosts/drops in one stat to the other.
RBY and GSC have no natures, and effectively 248 EVs max per stat with no overall maximum.
One idea is to run physical/special attack on the attacker, and defense on the defender. By which I mean, if 3rd Gen Gyarados were to use Waterfall on 4th Gen Blissey, the move would use Gyarados Special Attack (because Waterfall is special in 3rd gen) against Blissey's physical Defense (because Waterfall is physical in 4th gen.)
I think the mechanics could be hybridised. A few examples:
The single special stat in RBY could perhaps be implemented as an ability, that would transfer boosts/drops in one stat to the other.
RBY and GSC have no natures, and effectively 248 EVs max per stat with no overall maximum.
One idea is to run physical/special attack on the attacker, and defense on the defender. By which I mean, if 3rd Gen Gyarados were to use Waterfall on 4th Gen Blissey, the move would use Gyarados Special Attack (because Waterfall is special in 3rd gen) against Blissey's physical Defense (because Waterfall is physical in 4th gen.)