Nobody’s going to deny that Darth Vader is one of cinema’s all-time great villains, but you can also make a completely reasonable argument that the most fearsome Sith in the galaxy works much better in small doses.
As a looming presence across George Lucas’ first trilogy, audiences across the world were enraptured by Vader from the second he first burst onto the screen in A New Hope way back in 1977. The prequels focused on how young Anakin Skywalker was corrupted by the Dark Side and saved the final transformation until the very end, while all it took was a single scene at the conclusion of Rogue One to send the Star Wars fanbase into raptures.
That being said, we’re getting what Lucasfilm have already called the rematch of the century when Hayden Christensen returns to a galaxy far, far away in Obi-Wan Kenobi, and a new rumor is claiming that it’ll lead to a Darth Vader solo series. The “exclusive” from “trusted and proven” sources doesn’t offer any sort of details as to where the proposed show will take place, what plotlines it could potentially follow or how it ties into the larger Star Wars tapestry, nor is it the first time we’ve heard such speculation, so it’s best not to take it as gospel for now given the dearth of actual details.
Depending on how Obi-Wan Kenobi ends, though, it could well set the stage for a Darth Vader spinoff, but that’s something we won’t be finding out for a while. Ewan McGregor’s return is set a decade after Revenge of the Sith, so you’d imagine any hypothetical Christensen-centric series would have to unfold between then and A New Hope given that he’s a fully-formed antagonist firmly set in his nefarious ways by the beginning of Episode IV.