Besides being the pinnacle of Luffy's abilities, Gear 5 is among the greatest power-ups ever bestowed upon a main character in anime history. Luffy's strength flourishes with the Fifth Gear, unlike any other gear upgrade in the entire series. Except for a small minority, the Gear 5 was positively received by all fans worldwide. To pull them back from the dark side, I've discussed why Gear 5 is a perfect power-up for our protagonist Luffy below.
Luffy's Gear 5 is the Perfect OP Power Up (One Piece)
I don't want to conquer anything. I just think the person with the most freedom in the whole ocean is the Pirate King, said Monkey D. Luffy
The quote above is one of the iconic lines said by none other than Luffy, our beloved protagonist. He has always been a person who yearned for ultimate freedom in everything he does, and this is evident in his quotes.
Luffy has flexibility in his fighting style and uniquely fights with his rubber-like powers like no other. He always comes with distinct moves depending on the situation and that's how he upgraded to Gear 5 (see the full list of Luffy's gears here) over the years.