Well in the first series of HP i thought that he was not gegeven importance. But eventually i began to like him but in that "oh poor him" type likeness.
Cuz we c he has been always suffering bad luck but when he stood against his vrienden (positive thought) he presented a heroic act.
And then in the last part WHAO! he killed nagini!??
So the design of the character i guess is very balanced and yes i do, i do love Nivelle Longbottom. <333