Nami is more popular than Sanji. Also, in the pretimeskip Zoro and Luffy were very weak compared to many enemies and never acted like Usopp for example. So no, they don't change. I like Zoro much more for how he is than for his strength.
Bad comparison.
she isn't. At least no one care about her strength or personality (not anymore). She has tits that's all today even the author himself uses her for that.
zoro and luffy were very weak ? To whom ? Lol against their past opponents they were good. And in shonen you know MCs will become stronger that's what make them interesting.
If zoro and luffy were like ussop, one piece would have ended way before.
And sorry to deceive you. But overall speaking, 90% fans love strong characters because they are strong.
Only those who don't care, have different point of views.
The moment Zoro couldn't finish Kaido and fought King, we witnessed many zoro "fans" dropped one piece, started to blame him, and even hate others characters now.
People who really like Zoro and others strong characters for who they are, are rare.