I agree with you in general, you can build a natural ADA accessible trail of materials such as compacted stone dust, and they can be great, especially if maintained. I also appreciate a mix of both.
The big problem I have with the Reformatory Branch vote is not the loss of paving per-se, but the associated loss of also building safety features. The project included a tunnel specifically because the Concord road crosswalk was already known to be hazardous, among other safety features.
I don't think the construction timeline would have worked out to save this person's life even if the vote was positive, but regardless, after the vote someone has now been killed, walking her bike across the Concord road trail crosswalk.