So it's not fact they are exactly the same but with different skins? OH LOOK A STORM TROOPER HELMET IT'S COMPLETELY DIFFERENT
Each LEGO game scrapped elements from other games and incorporated new elements.
Batman's Batarang and hand-to-hand combat, as well as numerous other features.
Indiana Jones' whip, hiding in cover inside bushes or trash cans, and once again, numerous others.
Star Wars' use of the Force, easy-to-learn-difficult-to-master lightsaber combat, and astronomically(no pun intended) rich character customization.
As for Harry Potter, I have not played it.
Each LEGO game is different, each for different gameplay preferences.