Her powers are based in magic. You can make any kind of weakness consistent with that
I don't care. Every character gets low showings, It's inevitable that Diana does too. That make her being vulnerable a bad thing.And Rebirth is the best example of that. How many times she has been shot in Rebirth alone? Plenty of times. And she almost died in one of those. And in every single one of those cases where she got shot, the rest of her powers suffered. Because for example. We used to see Diana being able to deal with speeding bullets easily even while being blind. Yet in Rebirth. Every single time she got shot, or a villain(and not even villains with her level of strength and speed) pull out a gun against her, she seems to lose her speed all of a sudden and her fighting skills. How the hell can you explain the way Ruka had her getting shot in his rebirth run, or in priest jl? The same woman that is said to have the speed of a God. Who used to dance around speeding bullets like nothing, all of a sudden she got shot, she couldn't react fast enough against mere humans shooting at her in ruka rebirth run. And she couldn't react to a bullet that bounced off superman's chest in jl writen by priest and almost died. Things like this do not put her in a good position. It's not a complain about her not being superman equal. It's about the fact that when things like that happen, they make her look like a street leveler.
Making her bullet proof drastically lessens the amount of ways she can that iconic image. If she's bullet proof, you can only ever get away with using that iconography for irrelevant fan service. You can't create interesting set pieces around, you can't ever have her do it in a situation where she's being serious because if she's bullet-proof, because if she were being serious she wouldn't waste time showing off.Diana's bracelets won't stop being iconic if she becomes bulletproof. She can still use them(which she rarely does these days even though she isn't bulletproof).
Hell, even the "She's controlling the ricochets" fig leaf has fewer options if she's bullet proof, because if she's bullet proof, then any case where she needs to protect bystanders from being struck would be better handled by having her catch the bullets instead.
From where I stand, her being bullet proofs adds nothing, and only takes options away from her.