CDS has, in fact, observed that the armed forces are overstretched, and did so quite clearly to the Select Committee:
Link
You'll notice that despite the fact that he cleverly found a way of saying 'yes' to a question that he shouldn't really have answered 'yes' to (since it was a politically-loaded query), this went down badly in some quarters on pprune, while it was only picked up by a few journalists, since the issue wasn't deemed newsworthy at that time.