Well, you've got Avatar, those bitches cried over how that show paired everyone up. Nanoha just has faggots who argue over whether Nanoha is gay or not. Seven Arcs are just playing both angles, eventually they may pair her up with Yuuno or simply never resolve it (seems more likely and surprisingly in character for Nanoha, the girl who wakes up at 5am in the morning to train before going to breakfast).
Nanoha needs to have someone close to her severely hurt so she can fuck shit up with her cold ruthless rage. Sure, she may use non-lethal force, but she'll be damned if you don't almost die from the sheer amount of it she'll use, then make sure you are punished for your crime. Just hope her sense of duty doesn't break so she keeps following the rules.