Igor, to clarify, the ATPL(H) is REQUIRED for captains in the Ontario EMS, and ATP or CPL + HATRA for co's.
Co-pilots turn over regularly, as the pay can be pretty rough for them.
Captains are generally in demand in places where no-one wants to work.
As far as the ex-mil thing, the EMS/IFR business more closely approximates military ops. Also, most military crews are exposed to crewed helo's earlier and have less single-pilot habits to break, and generally more IFR time than civil pilots with equivalent total time.
**note: I said generally**
And about the sale of CHC's onshore ops, we'll see when they clarify what exactly they are trying to do with us, limbo sucks.