The Mane 6 ranked on how destructive they’d be as giant ponies.
1. Pinkie Pie. She would destroy countless buildings by bouncing around everywhere. She would have no self control and not even question what she’s doing. She’d probably crush cars and knock over skyscrapers with her butt for fun.
2. Rainbow Dash. She would fly around and dive into buildings and see how big of an explosion she could create. She’d also probably create a sonic rainboom equivalent to a nuclear bomb. I also think she would like to chase cars and airplanes around.
3. Applejack. If a building got in her way, she’d buck it away without a second thought. The buildings would crumble immediately. She has some strong legs.
4 and 5. I think Rarity and Twilight would be the same level of destruction. Rarity would do her best not to destroy too many buildings, because she wouldn’t want to get her hooves dirty and covered in all that debris. Twilight would probably be more interested in studying the buildings and cars, and would only crush them to study how sturdy they are. She wouldn’t crush anything for fun.
6. Fluttershy. She would be terrified of crushing any building or structure. She’d probably avoid walking and just fly.