Whether AC invests or not will NOT matter.
Airports are facing their own competitive situation, plus funds for capital improvements are hard to come by from airlines anyway, so process innovation is KING right now at airport authorities. YVR has long been leader with border control advancements, while YUL and YYZ are focussed on flow improvements throughout entire journey.
InTheAirGUy above notes what Copenhagen is doing, and I recently posted elsewhere that Gatwick is now partnering with airlines for a Self-Connect Baggage program so passengers avoid hassle of picking up bag and re-checking into another airline.
These programs ultimately shrinks terminal footprint and footprint at airports is remarkably expensive - the ROI exists and supported by the airline community, if not AC itself.
http://www.iata.org/whatwedo/passeng...ges/index.aspx