jamyskis: It's not so much about knowing how to as it is about developing the same kind of muscle memory that allows us to play using WASD+mouse on a PC. Switching to that from arrow keys and to mouse+keyboard from keyboard-only involved similar adjustments in the 90s.
timppu: I wouldn't call it similar at all. I think Duke3D was the first FPS game where I used mouse aim, and "WASD-like" movement (it might be I was using some other keys but WASD, but it doesn't matter). And I think I learned it up pretty much instantly.
Actually, I originally started playing Duke3D as I had played Doom 1-2 for a couple of years, with keyboard only, and when I eventually switched on mouseaim in Duke3D, I instantly felt a great relief, as in "Holy F, it's so much easier to play this with a mouse!". (I didn't get a similar feeling in Doom 1-2, probably related to it not allowing up/down aiming and generally having very heavy autoaim; and the default mouse setup was quite borked in Doom games (moving the mouse vertically moves you forward and backward... WTF?).
Also I know two kids who had no previous WASD+mouseaim experience (they were mostly console gamers before that, and playing mainly 3rd person view games like Spyro games etc.), and they seemed to pick up WASD+mouseaim quite fast for Minecraft.
How invested were you in the previous method of control? Because going the WASD route means splitting the movement between both hands and changing the combination of firing. Previously you generally had ctrl for fire, alt for strafe and space to open things. And the arrow keys for the actual movement. Meaning that you're using both hands more than you were previously and rather than just focusing on fire with the left hand, you're constantly using both hands for things.
But, with the WASD configuration, now you're adding the complication of aiming to that, and splitting the motion between the hands, which is going to require a bit of change to the brain to accommodate
Personally, I didn't care for it, because it meant completely relearning how to play games.. Well, that and the fact that it seemed to correspond to a point where developers were focusing more and more on multiplayer gaming rather than on single player campaigns with good AI. Well, that and them typically not spending much time and effort on level design or on making the challenge curve reasonable.
There were exceptions obviously, but the genre hit a series of potholes soon after that. ID refusing to have a singleplayer component in Quake 3, and ultimately Halo setting a new standard for how crappy the genre can be. There've been a few bright spots since then, but it's hard to come up with many games during the last 10 or so years that are actually worth playing in this genre.
hedwards: I get that this is a gaming website, but I have yet to meet an elderly person that wishes they spent more time playing video games or watching TV.
ET3D: You typically don't wish for things you can still do. My father has certainly taken a lot more to gaming (mainly solitaire card games) and watching TV since he retired. (You typically wish for things you wouldn't have done anyway. Meaningless regrets.)
That's certainly true as well. And it's a complete waste of time. I don't regret not climbing mount Everest. I regret not hitting on those women when I had the chance. Which was at least a possibility back then. Now, I find most women around here to be pretty shallow and generally self centered. But, overseas, the cultures seem to be a lot more reasonable in that regard.
jamyskis: It's not so much about knowing how to as it is about developing the same kind of muscle memory that allows us to play using WASD+mouse on a PC. Switching to that from arrow keys and to mouse+keyboard from keyboard-only involved similar adjustments in the 90s.
ET3D: Still, mouse is more natural for mouse users. I know when mouse aiming started it was an epiphany. For me it's kind of like touch for games which require selection. It's just the natural thing to do. Of course using a mouse by itself takes some getting used to, but most people still use mice. Maybe some years down the road when touch is more common people will have a harder time getting used to mouse aiming.
Indeed, I remember making the switch to keyboard + mouse and it was miserable. Fortunately, the FPS genre hasn't been very good since then, so I'm not missing much.
There's also vertical mouses that are a bit easier on the wrist as you hold them from the side, they still function the same way, but because of the angle, they're less likely to apply pressure to the carpal tunnel region.