PTEXIA said: we need a super robot taisen game-type for the mahou shoujos i'd place a good bet that the precures would be great tanks and be a gamebreaker
If the Precure are gamebreakers, then the Madoka Magica characters would be SNKBoss gamehax in comparison.
The Cures regularly deal with planet-busters for their end-series enemies and Walpurgis is something the stronger Cures might fight as a monster of the week. Gretchen is roughly equivalent to Black Hole from DX3 and he was manageable with 20ish Cures doing a combo attack together.
In a proper SRW game the Cures and Puellas would be split up along the Super Robot/Real Robot classifications rather than one being absolutely superior to the other; the Cures have the firepower/defense/HP and the Puellas have speed/evasion/accuracy.