It's not a question of if, but a question of when. Of course there's going to be a Resident Evil 6, but until Capcom officially announces a sequel, it seems content with promoting its various spin-offs and side stories: namely, Operation Raccoon City and Revelations.
The next numbered Resident Evil sequel may not be too far off, though. The game was recently name-dropped on a voice actor's resume, before mysteriously being pulled.
Siliconera discovered "Resident Evil 6" on Joe Cappelletti’s credit page, which included two other games "Capcom" games: Steel Battalion and Combat Wings. Since then, all mention of Capcom's titles have been removed from his page.
Cappelletti has been in a number of video games, most recently Modern Warfare 3. However, if his resume is accurate, "Resident Evil 6" will mark his first foray into Capcom's survival horror series. Perhaps that inevitable next game will feature yet another new character for the franchise?