Works? Sure. Well? Not really.
"To hear PC gamers talk about how first-person shooters don't work on consoles because the machines don't have mice, you'd think that's how it always was.
Not a bit of it. A lot of us playing in the early to mid-1990s on the first FPS games made do with just two handfuls of keys."
Well, sure, but none of you were very good, I'm afraid. ;) There is no significant competitive FPS player from the first few generations of FPS games who used keyboard-only controls, as far as I recall (and I was there, man). There were a few second-tier Doom speedrunners who used keyboard only, but all the top-tier players used keyboard and mouse. I can't recall a single notable deathmatch player who used keyboard only. It's just inarguable that the mouse represents a better control mechanism for rotating the player.
"I say this because the proof that FPSes are not at all dependent on a keyboard-and-mouse combo are the number of such games running on tablets, and if they can be played successfully there, they can be played on anything, console, PC or whatever."
I'd disagree here, too. I'd rather use a touchscreen than a keyboard or joypad to control an FPS, I think. I played a few FPSes on the Nintendo DS and found they played rather better than FPSes I tried on consoles with joypads. The touchscreen has many of the benefits of a mouse for player rotation - most significantly, you can easily perform a very small rotation or a very large one in the same amount of time and with quite a precise degree of control. Neither a keyboard nor a joypad is capable of this. I'd say it's sustainable to argue that you can play an FPS better on a tablet than on a console with a joypad.