The best Computer Keyboard would simulate the wanted operation of the traditional Typewriter and improve upon the faults.
I've used a Typewriter for many years, for those unaware of what that entails, briefly:
You press a key and there's a bit of travel where the slack of the mechanism is taken up (that is an undesirable action but a necessary part of mass produced mechanical keyboards.
Next there is the travel of the key, much too long in a Typewriter but part of building inertia for the swinging and striking of the typeface to the ribbon.
Once a certain amount of force has been applied the inertia should carry the typeface forward and you should be able to reposition your finger onto the next key - hopefully not too quickly or you'll get your typefaces interlocked and have to untangle them.
That's the critical parts of a perfect Computer Keyboard the feeling, short travel, the breakaway and N-key rollover.
Nowadays this can be done with a few springs, we don't need the linkage of the past.
An 'optical keyboard' seems an expensive gimmick. Hall effect sensors would be non-contact and more resistant to dust. They should work on the perfection of the feeling of typing before they add more LEDs.