I do wonder, how interested the Sith would be in Anakin. The author-supported interpretation of his prophecy is after all that he's supposed to destroy the Dark Side, something that would make him a walking mark to any Sith, old or new.
Vitiate likely would aim to corrupt Anakin, but not simply to make him as an enforcer, but to make him his next Voice, thus usurping Anakin's power for himself. Considering Anakin has Celestial-grade potential (he forced the Son and Daughter to kneel before him), if Vitiate succeeds, then he'd have succeeded in making himself into a god without needing to devour the galaxy. But if he fails, it's likely the Dark Council would bow before Anakin and make him the next Sith Emperor.
That said, the really interesting question is if Anakin was found by the Sith Empire
after the middle of the Great Galactic War, when the restriction on training Force-sensitive slaves was lifted. Anakin, despite all his idiosyncrasies, is actually quite well-suited to be a Sith, being a very passionate person. He just needed to be taught how to
properly channel his passion, something that Lana Beniko implies is part of the standard Sith training curriculum at Korriban.
"You were never taught to properly channel your anger."
- Lana Beniko, while telekinetically choking a Knight of Zakuul
The Jedi Order on the eve of the Clone Wars was really a poor match for Anakin, barring outliers like Qui-Gon, or even Dooku before his fall. Mace
might have better chances than most others to properly train Anakin, considering he's also a very passionate man, something he admits to himself in the novelization of RotS. However, the Jedi Order of earlier epochs, such as during the Great Sith War, would have been a better fit for Anakin.
That, on the other hand, calls the whole matter of Anakin into doubt, as he wasn't really born during a time of "greatest despair". Even when he was discovered on Tatooine, it was a dispute between a corpo power and Naboo.
That actually points more to Luke being the Chosen One, and not Anakin. That said, it runs into the problem of Anakin being so much more powerful than Luke. Luke was nowhere near a Celestial's power, easily overwhelmed by the likes of Abeloth, described by the Sith - Tahiri Veila, IIRC - as a volcano in the Force. Anakin, in contrast, like I said earlier, was able to overpower
TWO Celestials, and was even described by Darth Tyrannus as a
supernova in the Force.
