I'm well aware that the FAQ states that there will be no artillery because it reduces the excitement of the game...
2 points though:
1 - How many chinooks have you ever seen that don't have at least mounted machine guns if not heavier support weapons? Clearing the landing area prior to landing and/or protecting your troops during deployment just plain makes sense...
2 - If you require "spotting" in the form of using a laser designator or similar, artillery doesn't have to be a god-like super-power, it just gives you another way to attack a problem. It allows a lightly armed, mobile unit to designate a target for a more powerful artillery piece that is either fixed on the transport or even fired from the air/space. It is not risk-free or lacking in tension as the designating unit still has to have some form of sight (even if it's only on the outside of a building the alien is hiding in) and it's not necessarily overpowered because presumably it would require some resource investment to acquire such abilities...
Just a thought...