RE4 is my favorite in the series. Though I can understand some of the divide, as previous RE games were an action refinement upon the point-and-click adventure game genre, as was Alone In The Dark back in the day. RE4 made a break from that history, ditching the clunky controls and wonky camera angles and more difficult puzzles; it laid the groundwork for the TPS genre. Unfortunately RE6, rather than redefining anything, had to compete with the best TPS or even FPS games of its day with gunplay and bombastic set pieces and just wasn't competent enough to hang.
Point-and-click adventure game genre
Sweet Home (1989)
Alone In The Dark (1992)
Resident Evil (1996)
Resident Evil: Outbreak (2003) designed with multipayer in mind
Resident Evil 4 (2005)
Gears of War (2005), Uncharted (2007), their sequels and similar TPS games
Call of Duty 4: Modern Warfare (2007)
Resident Evil 5 (2009) with mandatory co-op
2012 brought with it 3 different directions for the series
Resident Evil 6, with mandatory co-op and 4 campaigns and all the bombast of modern shoot-bang games and all the QTE you could stand
Resident Evil: Revelations, a throwback to Resident Evil 4 style but with less calories and nutrition
Resident Evil: Operation Raccoon City, shoot shoot shoot shoot shoot bang bang bang bang bang
I think Revelations makes a better template for where the series needs to build off from judging by the demo, which I at least got some enjoyment from. But the series also needs to bring new things to the table--and top RE4--but more shoot-bang and multiplayer isn't the way to go, especially if they expect to compete in quality with other games. RE6 took a reported 600 member team to make it and had a crazy budget. Even from a practical perspective, I don't think they should bother to repeat or increase that going forward.
See also:
The Evil Within, from the creator of Resident Evil