It doesn't matter who's stronger between Sanji and Zoro
of course it does not matter. Sanji is fucking irrelevant.
EoS Zoro has a strength based goal of becoming the strongest swordsman. in shonen logic he will be one of the strongest swordsmen, if not outright the strongest that ever was.
this puts him above Mihawk, Rayleigh, Oden, Shanks, Roger, Fujitora, Shiki.... and the list goes on and on.
Roger used to be the benchmark for Luffy until Nika and Joyboy were revealed. Now they are the benchmark for him.
Which again leaves room for Luffy > Zoro since Joyboy/Nika may have been the absolute epitome.
Then again, Ryuma (I purposely left him out of the list before) is also said to be the epitome of swordsmenship.
Nika = Ryuma is possible as well. Which brings Zoro = Luffy back on the table, just as always.
Zoro = Luffy has the problem of pissing off 4 fandoms at once.
Luffytards
Shanksmongs
Sanjidiots
and last, but not least, the Admirats
that is the only reason it is so heavily opposed.