Yeah, hire the guy who made one of the seminal TV shows of the 90s, a show that has in its way shaped and influenced the television of the past decade as much as The Sopranos. If you keep on saying Buffy was a flop over and over, it won't make it true.
I'd say it matches perfectly. In the same way Favreau was an inspired pick for Iron Man due to being an actor's director and making heavy use of improv on his sets, or Branagh seems to be an inspired pick for Thor due to his affinity for Shakespearian drama, Whedon seems to be an inspired pick for his talent with dialogue, with ensemble casts, with bringing together long-term overarching storylines in excitingly climactic fashion, and for his inventiveness as a director, coming at what could be standard and predictable fare in an off-kilter way that makes it feel fresh and exciting.