Weak.
Super Saiyan 2 did not exist at the time the movie was released. It reflects the Perfect Cell Arc, which introduced Super Saiyan Grade II and III. Any of those can reflect the boost. If you are going by personal feelings as opposed to solid feats, I have no reason to conti
Using the name of the form as an argument is irrelevant as far as...anything goes. King Kai is a god and the king of the north universe. I guess that makes him stronger than everyone up until Boo, who is a demon and thus on par with him? Grade II is literally the Super Saiyan that has far surpassed Super Saiyan, too - I guess that makes it stronger than any Super Saiyan ever?.
Using fancy titles as an argument is just laughable, sorry. Broly doesn't have any feats that require even a measly 2x boost.