This thread is hilarious, but I'll try to give a serious answer.
In all honesty, I don't get why Luffy & Nami don't get together. Both know each other well enough to make the relationship work, after all, on top of having won each other's trust and respect.
No offense to Hancock fans, but she forms the Monster Trio of Simps alongside Coby and Barto. I just cannot see her as a serious love interest for Luffy at all. I mean, Luffy and Nami have done plenty for each other, so a romance between the two is believable. While covering her sisters' mark is essential, Hancock's lovesickness is more comic than dramatic, surely. Besides, Luffy himself has said no to Hancock's advances, so why would he backtrack exactly?