I enjoyed Leon's campaign most of all, because I felt that it best captured the atmosphere of earlier Resident Evil games. It's a real shame that Jake's campaign wasn't better, because I think Jake Muller is funny, interesting, and cool – possibly the game's stand-out character. I get the impression that you might not like Jake? And yes, I would agree that Ada's campaign felt like an add-on. It wasn't as fleshed out as the others.
Hahaha, that thing about the fingernails is hilarious! I had no idea.
I think people saw 6 as the perfect opportunity to vent their frustrations about the increasing focus on action, but in doing so, I think people went too far and criticised the game too harshly. I also understand that a lot of initial complaints about the camera and whatever were later addressed through patches, but I didn't play the game at launch. One thing I do like about 6 is how much you can customise it. Spend ten minutes toying around with the settings, and you end up with a completely different experience. I wonder how many people still don't realise that you can aim via laser sight?
I believe that the classic style hit something of a dead end. Although I absolutely love the older games, I don't think they offered much room for development, outside of small details like prettier backgrounds etc. It's one of those situations where there's no right answer – people would have complained if Resident Evil never evolved beyond the classic style of gameplay, and people were always going to complain as soon as the developers attempted something new. People just like to complain.