Probably not as much as Hitman series developer IO Interactive—developers of the first four games in the Eidos published series—probably are. While Sloan may list Rocksteady Limited as responsible for motion capture duties on a "Hitman 5," that may simply be due to geographical convenience. Publisher Eidos owns a portion of Rocksteady, which is conveniently located in London. IO Interactive is located in Copenhagen, Denmark, a bit of a drive and swim for someone like Sloan.
Employees at Eidos and IO Interactive ranking high and low have already made public their intentions to develop a Hitman 5, even if Eidos hasn't officially announced the game's existence. Granted, development responsibilities could have switched, freeing up IO to work on games like Kane & Lynch 2: Dog Days and Mini Ninjas, but we're willing to bet that Londoners Rocksteady are simply lending a hand in the motion capture department.
We're checking in with Eidos, Rocksteady and IO Interactive to get the story straight and will update if we hear back.
Mark Sloan [CastingCallPro - thanks, Garret!]