Canada has a very top heavy military, and I don't mean that in the sense that we have too much brass and too much bureaucracy. I mean that in the sense that we have a high level of engagement, training, skill, participation, and technology, but in a very limited/narrow quantity. We don't have a lot of "ground troops" (in every element), but we have a lot of capability, desire, and willingness to lead/control/command those troops (or fleets, or squadrons).
I think that we could put an AEW&C aircraft to good use, because those who are assigned to it would be well trained and experienced, and Canada would be willing to employ them at the "front lines", they'd just be controlling/directing/warning other people's forces.
Now, that's my hope and belief. It's entirely possible that whoever is pushing for this is imagining that in a future conflict this AEW&C aircraft is supporting an entirely Canadian (or mostly Canadian) "battle group", which I think is just silly. They're having a similar problem in the Navy right now. They are looking at some of the new capabilities and even existing structure of the USN and trying to replicate them, ignorant of the fact (or ignoring it) that a lot of those capabilities and structures are only possible (or economical) because of the scale of the USN.