I've just been reviewing the spec and have a few minor suggestions:
The Abstract currently talks more about what the spec doesn't do, and I think could explain more about what it does do. I suggest including some of the text from 5.1 Objective.
In the Abstract and Scope sections, I think "an Hypothetical" should be "a Hypothetical", as the H is pronounced.
In Figure 1 "all IMSC instance document" should be "all IMSC instance documents".
In section 6, "sequence of Intermediate Synchronic Documents" is referred to as Ei, but in section 7 it's referred to as En. Should these be the same in both sections?
I've just been reviewing the spec and have a few minor suggestions: