New cars have a few new features, all right, but the basics stay the same. They drive around on four wheels. These ninjas dodge tiles… that’s like having cars fly instead of drive. A flying car would easily fit the “OP” description, so, that might be why ninja heroes are considered OP by average players.
Normal families have bonuses for 2/3/4/5 heroes on the battlefield, ninjas are fortunately limited to 2/3 heroes, anything above that would be insanely OP… just imagine, if the bonuses went on for the 4th and 5th ninja, a 5 x ninja defense, each of them having a 20% chance to avoid tiles and specials and a 20% chance of counterattacking with 150% damage. And that’s always active innate abilities, not special skills.