Turntables did not start with 100mm pitch faders. I've seen pre-tech 1200s turntables with short throw faders and pitch knobs. Hell the Technics sl1800mk2 and sl1700mk2 both have knobs rather than faders. 100mm pitch faders stuck because they are largely thought to be the most comfortable to mix on.
Lots of people go outside of 6% and hell, a 50mm fader isn't really long enough for that. On a 1200 you get +/- 4% on a 50mm fader and on a CDJ1000 you get +/- 3%. That means that if you're playing a 128 BPM house track you can only select from tracks between 125 and 131... You might be comfortable with that but my Jungle collection ranges from 140 to 240 BPM and I literally could not mix within such a small range.
And if you're using standard 8 bit midi you're going to have to go even lower to +/- 1 or 2 % as the resolution will be too low to have decent pitch accuracy with a range any higher...
If you're going to have unusable pitch faders you may as well get rid of them altogether.