I've pushed a version of the ICD with individual stream properties provided as sub-elements of . This version is on the branch named, appropriately enough "properties". This suggested improvement for das2.3 streams was not universally agreed upon, thus it is not on the master branch.
I think supporting this change is worthwhile and I can add code to handle it in libdas2 and das2pro in a couple of hours at most, but don't want to make this move unilaterally.