We should wait for the official translation, but whoever denies that this whole "skill" nuance smells iffy is deluding themselves.
Nuancing a statement isn't meant to confirm but to question it. If you want to make something clear you just don't nuance it. If the "skill" translation is correct and Oda wanted to portray Mihawk as undoubtedly stronger than Shanks as many here assume, then he'd have no reason to nuance it as a "skill matter"; just state "even stronger than Red-haired Shanks" and that's it, easy.
It's not the first time that swordsmanship has been nuanced: Koushiro stated that a sword that can't choose what to cut isn't a real sword to him; Databook addressed Vista's swordsmanship as rivalling Mihawk's (and we all know Vista is far weaker than him), while Ace's novel specified Vista's swordsmanship to be stronger than Thatch's; Zoro addressed that King never claimed himself to be a swordsman in spite of fighting with a sword because of his overall versatility; and now this "skill" nuance, completely unnecessary if you just can't dissociate swordsmanship mastery from overall strength.
Many fanatics will jump on me; I couldn't care less: whoever believes there's a clear answer to the "Shanks versus Mihawk" debate is delusional. Mihawk has his title; but Shanks is pretty much Oda's self-insert, the main character's role model, the one stated to be closest to being Pirate King in terms of his spirit (and spirit tops everything else in this story), one of the few mentioned by Kaidou as capable of fighting him (alongside pretty much the powerhouses of their eras) and, more importantly, the epitome of "conqueror's haki". In a world where the main character's dream is to become Pirate King, and Pirate King being the conqueror atop conquerors (the ruler of them all, basically), we can't just assume so happily that the guy who just scared a freaking admiral with conqueror's haki alone is under a title on a much more nuanced concept than many people seem to think, as swordsmanship is.
Again, we will see what the official translation has to say.