I'm not a huge rail-shooter fan but I do enjoy them. Some of my fondest memories from childhood are playing various Time Crisis and House of the Dead games in arcades. When it comes to rail-shooters at home though, I generally only go for ones which really appeal to me for reasons other than gameplay. The chief examples being Resident Evil: Umbrella Chronicles and Darkside Chronicles (which was a fantastic game).
I don't really know where the genre can go to evolve but, frankly, they're fun enough as it is so I would be fine if they stayed more or less the same.
The worse case scenario for a rail shooter is a series which was previously open to player control making the transition to this limited perspective. This was the case with Resident evil which has never fully recovered since.
I don't understand, are you saying Resident Evil as a whole is now a rail-shooter series or just saying that the rail-shooter spin-offs are bad?
In my opinion the 'classic' RE games have far less player control than the 'modern' ones. Resident Evil 6 has unprecedented amounts of control compared to, say, RE2 or Code: Veronica, for example.
The Umbrella Chronicles and Darkside Chronicles were very typical of rail-shooters, with Darkside using a lot of camera techniques to try to immerse you more in the story. The Survivor games were just... I don't even want to talk about them. Ok I will. They were hilariously awful. Like, so bad you can't help but laugh. But the series' later experiments with rail-shooters were much more well made and interesting. Heck, Dead Aim actually let you run around and explore a ship, it was much closer to RE4 in terms of gameplay than it was to the other rail-shooters.
I don't mean to sound like a twonk, just trying to understand what you mean when you say the series has "never fully recovered".