That's just a cheap excuse from y'all. He should perform better fighting wise and that's a fact. What's the point of the story being the focus if he's dumb ass keeps allowing people to get hurt/get killed. Or is that also part of the story?
That only comes from your expectations of him being too high, a common problem among you Sanji fans.
In fact he was always portrayed to be flawed (like how he can't deal with women, when other nakama doesn't have any shortcomings). So, he won't get an ideal 100% execution to everything.
And "allowing people to get hurt/get killed"? What kind of manga are you reading? Oda literally uses Sanji to be a savior all the time. That's the opposite of allowing people to get hurt/killed.
Or are you deleting your memories from scenes like Sanji saving Luffy in Arlong Park's pool, Arc Maxim, Gate of Justice, Doffy's onslaught, Momo's execution, etc?
I get that you're butthurt Oda didn't write Sanji like the way you want him to, but these scenes are real and actually happening on panels.