Being a blond, overemotional warrior prince who has a strict father and a strong guy he treats as his rival = getting treated like shit by your author, sadly.
See: Vegeta (constant jobbing, Bingo dance etc), and Thor (fat Thor, everything Jason Aaron wrote with him post-Mighty Thor) as two examples of what I mean.
Admittedly neither of them has had to deal with being portrayed as an actual gooner the way Sanji has though.