I am a typist, I learnt to touch type some twenty years ago on manual typewriters, and just about every computer keyboard in existence just plain sucks. The best electronic keyboard that I ever came across was on the old IBM Selectric typewriters, from the 1960s/1970s, the ones that many know as the “golf ball” typewriters (so called, because the typefaces were spread around a ball, about the size of a golfball). They were also a damn good typewriter (the fastest I've come across, printed well, you could get all sorts of paper and card to go through them, and they lasted well over thirty years).
Unlike many computer keyboards, its keys were not made of porous plastic, which gets absolutely filthy and is nearly impossible to clean. Nor were the keys made of soft plastic that wears down with just a few months use. Nor did they wobble about and jam (because the wobble moves them in a way where they won't move vertically down). It had keys made of a decent construction in every way:
The keys had the right amount of resistance. It didn't hurt to type, unlike some manual typewriters. The force required to press keys fully home was just right, for the full length of their travel.
The keys had the right amount of travel to them. You didn't get RSI, like with some computer keyboards, because your fingers move enough with each stroke. You could type like a proper typist, where you strike the keys.
The keys hit a stop, when pushed all the way, similar to how a real typewriter works. And, by that time, the character had been typed. You didn't really need any other form of feedback to confirm that you'd pressed a key properly. Also, the resistance against pressure was enough that you didn't feel like you'd stabbed your fingers hard into a solid object, when it finally did hit the stop, unlike many manual typewriters.
The keyboards had good rollover handling. If you were to hit a quick succession of keys, even if the prior keys hadn't finished releasing, each key that you struck was typed in the correct order, and with no mistakes (unlike with manual typewriters, and many computer keyboards).
The keys didn't repeat if you held them down, they repeated if you pushed them deeper than the normal stop point. This meant no accidental repeats, no delay waiting for a repeat, but repeating when you needed it, instantly, and simply.
The keys were quiet to use ('twas the typewriter that was noisy).
The keycaps were made out of decent quality, long lasting, plastic, and with a good shape to them.
Bad rollover handling. If you press several keys quickly enough that some keys get pressed while others haven't yet released, you get unpredictable results. You might get all the keys you pressed, in the right order, but you're more like to have some of them missed out, or some random letters inserted.
Bad multi-keypress handling. A common requirement with computers is to press a series of keys together, for a special purpose (e.g. CTRL, ALT & F1). Some keyboards just don't handle this well, at all.
Not enough travel in the keys. Having to doing lots of short, sharp, tiny precise movements, is a big contributor to RSI. Many laptop keyboards being amongst the worst—you either try to press too far, and come to a dead stop suddenly, or you have to really restrict the amount of movement you make (which is even more painful).
Mushy keys, where you feel like your pressing a key mounted on cheap squashy foam.
Keys that suddenly change their resistance to pressure, once you go past a certain point (the ones that work by you depressing a key mounted on a bubble-shaped bit of flexible material).
Buckling spring keys, that make a hell of a racket while you're typing.
Keyboards which are internally constructed out of overlaid plastic film matrixes that break down, or get dirt between the layers, eventually giving you some keys that won't work, need bashing very hard to make them work, or get jammed and repeat.
Cheap plastic keycaps, that have sharp edges, tops that wear down really easily, shafts that are sloppy with keys that jam if pushed off centre, and legends that wear off.
Inconsistent placing of some keys on some keyboards that all claim to use the same layout (e.g. the backslash key, the enter key, backspace key, printscreen/insert keys in each other's places, etc., on US keyboards).
Dumb placement of keyboard status lights. Why is the caps lock indicator light rarely ever near the caps lock key?
Out of balance keyboards. You can't type with the keyboard on your lap, as you've got a number pad on one side. Either you try and type with both your hands over to the left, which is really awkward, trying to keep the board balanced on you. Or you centre things around the home keys, and then the right hand side of the keyboard hangs in mid air, with nothing on the left hand size to counter-balance it. Nobody, since the early days of computing, has the sense to put the F keys left of the keyboard, to balance things out.
Apart from sorting out all the promblems I mention above, and re-implementing the good things mentioned further above, it's about time that some updates were made to keyboards:
Some extra keys for typing proper punctuation, accents, and other commonly needed symbols, and without difficult to remember, or type, key combinations. We should be able to type opening and closing proper quotation marks, without some twit typing two apostrophes instead of using a double quote, nor typing a grave accent where there should be an appostrophe or single quote mark. We should be able to easily type things like the different dashes, copyright symbols, etc.
Easy ways to type all needed symbols. Just because I have a US-English keyboard (on my Australian computer), doesn't mean that I don't need to be able to type a British Pound (monetary) symbol, a euro symbol, or a character from a foreign alphabet.
Copy what they did on the Mac—let you plug that other monstrosity of modern computing, the mouse, into the keyboard, so that you don't have to have two cables trailing away. Oh, and make the keyboard cable long enough. These days it seems the desktop box has been usurped by the tower, whether you want one, or not. Yet the keyboard and mice cables are short ones, really only suitable for a desktop box that's right next to them.
Any time I ask a shop for a good keyboard, I'm shown crappy ones that are more expensive because they've got extra buttons, or are shaped in some different way. None of them were actually any good for typing. IBM could do the world a huge favour, and make a computer keyboard just like they used to have on their Selectric typewriters.