What information? Sure, sanji isn't as strong as first yonko commander level. but there is no evidence to suggest he would win against the second, third.... or ninth for that matter. Overall, sanji has not shown a single thing which suggest he is particularly competitive at the yonko commander level.I'm basing Sanji being that good on the information from the manga. He's stronger than a member of the Flying Six but for sure not at Yonko First Commander level.
Your idea of a "meaningful" power up seems a little one sided. One of his dreams was the Invisibility DF, his fighting style relies on High speed strikes and particularly decent CoO. The suit amplifies those already established abilities on top of durability.
You idea of anyone "compensating" for haki means they are weak is just odd considering its Kaido's scales and not his haki make him as invincible as he seems. All that matters is that your haki is strong enough to hurt your opponents. Luffy vs Katakuri proves this. Katakuri had superior CoA and Luffy could still hurt him badly.
Sanji's Raid Suit brings a dynamic in future battles that we are in desperately need of.
Well, my post isn't about sanji's dreams and feelings. Clearly my point is more on how his haki is simply lackluster and the raid suit simply not compensating for it. We already have zoro and luffy being capable of extending their haki beyond their bodies and meanwhile sanji has not even shown hardening...
What dynamic? The raid suit acts as an armor and makes sanji invisible but otherwise nothing we know of suggests it will do anything dynamics wise. Sanji's overall fighting style would by all appearances remain exactly the same. The suit certainly acts like an armor and would likely enhance his offense and speed but that is about it. I would even argue the flying bit the suits are capable of are largely irrelevant to sanji since he can fly anyways. And sure, the suit could do more like, say, enhance sanji's fire somehow for instance. But the fact remains that a haki upgrade is simply a superior alternative to a suit. As in, if sanji had a choice between a haki upgrade and the suit he'd definitely be substantially better off with the haki upgrade than with the suit. Just look at luffy. Learning the advanced version of CoO got him from being much weaker than katakuri to being at least a match to him. And the current armor haki upgrade will apparently get him to a point where kaido can at least feel his attacks, which is massive. zoro will likely get a comparable boost from his current haki training as well. Sanji is simply getting the worst of the powerups around. Zoro is likely on his way to soloing a relevant yonko commander meanwhile sanji would still likely get owned by the likes of doflamingo....