Any weird/controversial opinions? I'll start. Before the remake, the best version of Resident Evil 4 was the Wii version. The Wiimote controls old Resi's tank controls better than any other controller at the time. The PC version had a bunch of little bugs and detractors that the Wii version just doesn't have.
I'll extend this by saying that the Wiimote is actually pretty damn good for shooters, and particularly good for accessibility. Not having to cramp up my hands to press buttons is awesome for having arthritis. Aiming with the Wiimote and moving with the nunchuck just feel really natural, you barely have to move your fingers for anything.
It's definitely not the worst. But I consider it overrated (considering how it's perhaps the most popular). Hands down I'd put 9, 10, and 12 above it. I'd maybe even put 8 above it depending on my mood.
The first game is probably the worst. It's very basic. Arguably it's unfair to compare it to later games, given it's age (as an aside, I've only played the GBA remake of it -- I probably wouldn't be able to stand the true original). I'd say 1 < 3 < 2 < 5 < 4 < 6 < 15 < 13 < 14 < 7 < 8 < 12 < 9 < 10. And honestly I could drop 15 a lot further down depending on my mood. I'm clearly biased against the 2D games.
I don't really get why 6 is so popular (there's even another person replying to you mentioning it). It's the best of the 2D games hands down, but I didn't find it as good as really any of the later games. I think I put a lot of weight in the ability for graphics to be able to show emotion and make settings more interesting. I utterly adored the cutscenes that began with the 3D games.
I agree with you to a lesser extent when it comes to the 2D games. It's so much harder to show emotion. I love V, but I feel like there are a lot of story beats that would land a lot harder in a game with good graphics.
Having said that, I prefer the gameplay of some of the 2D games to some like IX and XV. And the 3 I have played aren't as grating as others like VII, IX, and XV. So while they can only be so good, they also aren't as bad as some of the others get.
1 is nice comfort game. And honestly, beating the big villain at the beginning of the game and following the time loop would be subversive if it wasn't the first game in the series.