This is proving how ignorant we are -_-. Drop him off because he has pink hair, a pink scythe, and throws flower petals? This is why gay men are so afraid to go in the open sometimes.
Marluxia's power is Nature (or Flower), nature consists of life and death as well. So, yes, he does have death.
And first off, Marluxia is in no way a noob. He acts serious, stern, devious, and his plan was going to be genius, if there wasn't a double agent in their mists. Seriously. Sora could've have taken down most Org. members, as proven in CoM and KH2, and while Xemnas might be hard, with Larxene, Sora, and Marluxia teaming up, they would have a chance, especially if Sora powers up. There could've been a more productive way, but they couldn't take risks on being watched.
That, and he in no way acts like the color of his hair. He's 100% testorone. My first impression was that his body and manliness (I dare you to tell he doesn't look fit and strong) took away from the hue that he sports, and he has this commanding presence, he's just so calm, until things didn't begin going his way.
About pink, he doesn't blow flower petals. They are flowers, but they're sakura, cherry blossoms, which in Japan represents samurais, and their falls. Sakura also represents death, so there you go again. Not only that, but pink in Japan is considered manly (perhaps due to this), and with Marluxia's boldness and pride, he fits the metaphors perfectly. Even if he was meant to be a girl, Nomura changed him to take this thought away completely. If you doubt me, go look for information on it.
That's why he was made to be like a Grim Reaper, with black cloak, and cool scythe.