So currently looking at Dialga and Palkia, Origin Dialga and "Altered" Palkia would be preferred?
Dialga gets swaps Atk and Def, and Palkia swaps Atk and Spe. I also believe that Time and Space Balm are required for them to change forms, which is why "Altered" Palkia would be better. It can still hold items like Scarf, and for Ubers it wouldn't outspeed that much with most of Ubers being <100 base Speed. Origin Dialgia would also be better since "Altered" Dialgia would only really use Type Berries and Leftovers and maybe Specs. Both would still be viable too.
Dialga gets swaps Atk and Def, and Palkia swaps Atk and Spe. I also believe that Time and Space Balm are required for them to change forms, which is why "Altered" Palkia would be better. It can still hold items like Scarf, and for Ubers it wouldn't outspeed that much with most of Ubers being <100 base Speed. Origin Dialgia would also be better since "Altered" Dialgia would only really use Type Berries and Leftovers and maybe Specs. Both would still be viable too.