if your talking about the factory note quantizer then there are two different approaches...
a) produce your own version, and release in the community library under your own prefix, see process as mentioned by @philoop
b) fix the factory version, this requires you to clone the factory library, and then issue a pull request.
(or you can do (a) and we can consider it for moving to the factory, just do NOT use the same UUID, it must start off as an alternative)
as for the note quantizer in the factory.
I think many people have different expectations from what I implemented (which I think works correctly in what its trying to achieve) ... basically most people expect it to just 'round' the result to a scale.
this was not what I was after when i implemented it... I wanted to not have gaps....
the difference is, imagine the following note numbers (numbers are not correct, as i cant be bothered to look up the correct ones 
just an 'example') being mapped to C Major.
first column = note number
second = midi note
third = my requirement for it to be in scale
fourth = what many expect
0 C3 C3 C3
1 C#3 D3 C3
2 D3 E3 D3
3 D#3 F3 D3
4 E3 G3 E3
from here you can see, I want to from a number sequence 0,1,2,3,4 to a scale, rather than round from one scale to another... and yes to do this, gets a bit convoluted, because I need to be able to offset the input and output ranges for it to work reasonably.
so this is a case, where the object just doesn't do what you are after... and perhaps the description is a bit misleading? (perhaps its should just be a scale object rather than a quantizer!)
anyway, issue we have, is I've known this for awhile (a few have brought it up, and i think there may already be alternatives in the user library) BUT I cant really change its behaviour, since this would break patches that do use it. (and I do use it 
)
as i said, what i could do is rename it... (scale seems reasonable , the more i think about it)
and then this would free up the quantiser name, to be with the 'rounding' method, which I think is what most were expecting... and as you say, that object is pretty simple to implement.
(I think what I'll do is create an 'ultra simple' one, with few controls, this will then allow the community to create more 'interesting/elaborate' ones)
