Sanji really gets the short end of the stick, not only is his personality plagued with one of the most annoying tropes/gags in history (which bogs down his character a LOT), but he's constantly mocked and called weak too. In fact take a second to look up the word hypetool. I won't say more than that, because I don't even need to.
If Oda respected his power level a little more and also got rid of that absolutely horrible pervert "gag", Sanji would possibly be my favorite (or second favorite, I don't know, Franky is just too goated for me to have anyone else as my #1 favorite) Straw Hat.