Slurs and dynamics can be linked i.e. you change them in one staff and they change in all the linked ones.
Would it ever be feasible to have local chords that can be linked? Perhaps with an option of automatically linking two local chords if they are the same or copy/pasted?
Is this even a sensible idea?
Yes, but…. 
Slurs and dynamic don’t have to deal with pitch. What happens when you have a piece in a key where it is easier for another instrument to be transposed? I’m thinking of something like a piano playing a piece in Eb (or even Db) where a guitar player might throw on a capo and play in D (or C). – just a quick observation.
I guess the software could take this into account but that sounds a little more complicated than slurs and dynamics. It’s worth considering… 
— Jim
Good point - didn’t think of that.
I guess the same thing that happens now?
For the specific case of using a capo, you don’t have to enter local chords on that part. You can set up the instrument to transpose the chords automatically.