This seems to have gotten into a lot of different things, rather than just RE5.
To be honest I think RE5 was decent, if not exceptional. I can forgive it going into action movie territory because it's an ongoing series, following the same protaganists. The whole "OMG there are zombies" works the first time you run into them, but that can only happen in the beginning, once you presumably survive the zombie scenario a time or two you start to get ready for it, and the whole "horror" vibe doesn't make sense anymore. In the case of "Resident Evil" it wound up actually following the premise through fairly logically, by actually seeing people with some resources taking the threat seriously, and using veterans of zombie/biohazard outbreaks to deal with certain situations. Criticisms from fans saying it's not a survival horror game series anymore are fair, but then again how could it be if it's going to continue this narrative with any kind of common sense? I tend to be less critical of RE for no longer being as horrorific as I am with the industry for not developing more survival horror games, which by definition requires new franchises. I am sort of hoping "The Evil Within" will turn out to be the game/new franchise horror fans have been waiting decades for now.
To be honest RE5 seems to have mostly gotten it's attention and negative reactions from the allegations that it was somehow racist, for pretty much portraying African tribals as well... African tribals... while allowing bad things to happen to them in the course of the story. This is pretty much it's claim to both fame and infamy, as RE5 has become almost indecipherable from that controversy, and pretty much anyone who knows the game has an opinion on that, and it tends to also influence what their overall reaction to the game tends to be.
Speaking for myself I thought the game was just okay, for the same reason that it's rare to really got "wow" when a movie franchise hits five installments (usually). I mean you not only know what to expect, but your logically diverging so far from what initially got people interested in the series and focusing on minutia and entirely new material to carry it forward. The biggest problem with "Resident Evil 5" in my opinion is that there is more "Resident Evil" afterwards when they really could have wrapped it up here... but you know, every potential dime needs to be wrung from a franchise right here and now. Nobody believes in "leave them wanting more" anymore, or that perhaps with time genuinely good idea (ie not Resident Evil 6 or Racoon City) will come along presenting something new to do with the material that can carry it forward without becoming a pathetic money grabbing cash in.
For the record I think this is the problem that sort of hurt other survival horror franchises as well. "Silent Hill" pretty much turned out the way things like "Nightmare On Elm Street" or "Friday The 13th" did for example, re-using the same basic idea which was kind of crazy/campy to begin with, until the only thing left was to turn it into a sort of self parody. In say "Nightmare On Elm Street" it became less about the horror, but the FX involved in people's fight scenes with Freddy (before they die), which is an oddly kind of what happened with Silent Hill, where it turned less into "OMG, an evil town that conjures crap from inside your mind" into an exercise in what kind of damage you were going to do to it's various minions. Pretty much the same thing happened when it went from being sort of "cool" to see one of Freddy's victims briefly give him a bit more than he bargained for, to the point where it was one surrealistic fight scene after another, all following the formula of "Freddy loses, regenerates, then comes back and kills the guy who clobbered him".
In short, nothing is wrong with the ideas behind the franchises, or the franchises themselves, it just went on too bloody long when it needed to be tied up and new franchises created.... and as I said, I'm hoping "Evil Within" will be the start point of a new franchise that will give us a few decent installments before it inevitably turns into the same thing. We just need to hope that the creator/company will know when it's time to wrap it up on a high note, and move to a new franchise.