In the appearances he did have, he hasn't been impressive since his first one, and that's because Luffy had no way of dealing with logia users without haki or their weakness. After that, he's not shown anything impressive, and it could be theorized Luffy can beat Smoker easily now. Sanji would have a harder fight, but he's shown enough feats that he would likely beat Smoker.
I of course ignore everything that happened pre-TS for this debate.
Luffy would no-diff Smoker in Punk Hazard if he went G4. Now he wouldn't even need it for a low-diff. But I question Sanji's feats.
Which single, actual fights has Sanji had? His skirmish with Doflamingo was short and took place in the sky, but in any scenario Sanji would have lost to Doflamingo anyway, and so did Smoker. Against Sheepshead or someone on Zou, he did beat them. He also beat up his brother or brothers and was forced to stay still and take their beatings for whatever reason (collar or holding a maid hostage? I forgot). Dunno if you' consider that a win though.
And against Page One he did win, at least in his objective. I count this because fighting was involved, and Sanji did manage to at least get Page One away from the citizens and knocked out long enough to get away undetected.
But also, he's rarely had fights after Punk Hazard whereas the last of fighting we saw from Smoker, he was wrecked by Doflamingo.
I could question that Sanji cleared his objective because he also voiced an additional one that he certainly didn't achieve in that fight (taking down an enemy officer to lower their forces before the big war), but Sanji wore his Raid Suit for that fight so it's pointless talking about it when my positioning on this topic, that spawned this conversation, is this:
If this was on Punk Hazard, I personally think Smoker would beat Sanji black and blue given their respective performances against Vergo.
However, with Sanji's growth and his Raid Suit I think it could go the other way now.
Sanji is very likely stronger than P1, perhaps even without his RS (though it would be a harder fight) but if we are talking about actual victories (a criteria that you brought up) Sanji has only really defeated one of his brothers, Yonji, and we don't know where that guy ranks as he seems to be the weakest of the siblings.
Smoker was beaten by Law, Vergo and Doflamingo, and it's true that it isn't a great track record, but Law was defeated by 2 of the same guys in the same arc and it's pretty clear he would have lost to Law too, so since we can't compare victories, we must compare how each of them fought with the same opponents.
I think it also comes down to whether Sanji can touch or hurt Smoker who's smoked up and spread out, but didn't Doflamingo or someone say that doing that wouldn't keep Smoker safe?
To be more accurate, Vergo told him that he shouldn't keep turning into smoke and expanding because he was just becoming a larger target, yes,
but that lacks context.
Smoker vs Vergo and Sanji vs Vergo are the only fights we can use to compare them as they were then, since Doflamingo vs Smoker was omitted but it seemed to be just as much an instant-defeat as Doflamingo vs Sanji.
I already made a post or two with this info but I'll expand on it with pictures as food for thought.
Sanji vs Vergo
The fight starts with Sanji blitzing Vergo with Diable Jambe.
Diable Jambe was Sanji's strongest form: attacking with flaming kicks. That kick to an unsuspecting Vergo achieved slight bleeding from the mouth and nose:
This was followed by an even stronger attack from Sanji. While still using Diable Jambe, this time he used a named attack:
What did he achieve with this? A very slight bruise on Vergo's face and no new blood:
This is explained by Sanji: Vergo used tekkai to block that second kick. The bruise on his cheek was just like the bruises on Jyabura when he took Diable Jambe with his tekkai. Just marks of burning rather than direct damage. However, in Jyabura's case, the pain from Diable Jambe's fire made him relax his tekkai and take the full might of Sanji's kicks, while Vergo properly tanked it and took zero damage from Sanji's kick:
Then it was Vergo's turn to attack. He rushed at Sanji and kicked him. Sanji blocked it with his usual blocking stance but he failed and his leg cracked:
Some people argue that the fight continued afterwards "and so Sanji's fracture doesn't mean much", but that's not entirely true. Sanji was still moving around enough to dodge and block some fast kicks, but it was a single page after the crack that Vergo was interrupted and had to run to Law, so Sanji only fought for a single page after the crack:
And to further emphasize how badly Sanji was hurt after mere moments of fighting, Oda added this scene:
Sanji's leg cracking can be explained by how hurt his body supposedly already was, but he still failed to surpass Vergo's tekkai with his diable jambe, and there's no reason to believe Sanji didn't use his haki in those attacks.
Smoker vs Vergo
If we look into Smoker vs Vergo, the fight consisted of two parts separated by scenes that took place elsewhere.
The first half of the fight started with Vergo immediately getting more serious than he ever got with Sanji, despite experiencing Sanji's strongest kicks from the get-go:
Vergo immediately taking out his bamboo stick is a big deal, because he's known as "Demon Bamboo" Vergo; his bamboo stick is as characteristic of him as the straw hat is to Luffy. He didn't choose to take it out against Sanji despite that fight starting with him getting kicked straight to the face twice with Diable Jambe, but he chose to take it out the moment Smoker charged at him. This was not because of Smoker's jutte, because:
- Vergo is not a Devil Fruit user, so he would have no big problems touching it.
- Vergo is more than strong enough to block haki-coated bladed weapons if the attacker's haki isn't strong enough:
For the rest of the first half of the fight, Smoker was portrayed as pretty equal to Vergo, yet slightly dominating him:
- Smoker succesfully dodged his attacks multiple times with his powers, which also provides him with superhuman mobility and shows that he
can use his DF for defensive purposes against haki users.
- He succesfully blocked Vergo's kick with his leg, which can be used as a direct parallel with Sanji failing at doing that.
- He succesfully punched Vergo right in the face with more success than Sanji kicking him twice with Diable Jambe. With a single hit he got Vergo bleeding from the place he was punched at, and shaking a bit when getting up, which is used to showcase he failed at using tekkai to block Smoker's fist the way he previously did against Sanji's Diable Jambe.
Then some other scenes happened and we jumpe to
the second half of the fight.
Smoker's portrayal suddenly changed a lot out of nowhere, but that's explained later.
Vergo was still bleeding but so was Smoker now. Smoker was suddenly having trouble keeping up with him, yet he was still getting hits in and adding bruises to Vergo's face:
This is when Vergo told him what you mentioned and immediately defeated Smoker with a single all-out blow:
However, this lacks context, because Vergo was being played and it was explained a single page later:
Vergo didn't notice Smoker was "becoming smoke and expanding" to steal from him and he didn't even notice his intentions. As we can see in the pic I just posted, Smoker not only stole the heart; he even got it over to Law without Vergo noticing. He did so with the attacks from the previous pic that seemingly "missed" Vergo, which means Vergo defeated Smoker with a full-powered blow just at the moment Smoker was more preoccupied with sending the heart back to Law than with actually fighting him, after he flawlessly stole something from his clothes mid-fight.
The only thing Vergo noticed of this all is that Smoker wasn't fighting as usual:
This makes more obvious that:
- Vergo was outsmarted.
- Smoker accumulated damage and was brought down because he was not actually focused on fighting.
- Smoker doesn't usually just "become a larger target" and is not usually that easy to deal with him just by using haki.
We only need to look at other logia users to see that there are many ways to use their powers for attack without turning into their elements, and even when defending, they have ways to use them to move around or to dodge with CoO. In this very fight Smoker showed he's able to use it for dodging and mobility without needlessly expanding and without getting hit.
Vergo didn't use full-boy hardening against Smoker nor Sanji so it can be argued that he didn't go entirely all-out on neither of them, but he certainly took Smoker more seriously despite experiencing Sanji's strongest kicks first-hand.
So I'll say it again: if we compare what Smoker and Sanji showed at Punk Hazard, Sanji is outclassed and would lose to Smoker. Even if we make excuses for Sanji's durability and we focus instead of their attack power, Smoker blows were objectively more powerful than Sanji's when hitting the same target.
It can also be argued that current Sanji vs PH Smoker would have a different result, but that's not fair on Smoker nor what I was discussing.