I do this all the time; I book my long haul flights in and out of a region on AC on one booking, and then book flights inside a region on separate bookings with whatever airlines make sense. It allows for the flexibility to adjust intra-region travel without having to change the expensive long haul flights to and from Canada.

The flip side of this is I need to allow for enough time to connect because AC isn't obligated to do anything for you and I wouldn't rely on a concierge or anyone else doing me a favour. The one time I ended up cutting it close (making a DEL-YYZ return home) I was proactive and called and was told to rebook my flight if I thought I was not going to make it.

So for example when I was in Australia this year I flew Qantas back to SYD about 36 hours before AC 34 back to Canada. I just spent the downtime in SYD, which is not the worst thing in the world to have to do ;-)