I'll just barrel through this.
I love the psi-implant idea, though the idea that the first one would allow mind-control does unsettle me a little. I liked the element from X-COM: Apocalypse; while the psi-weapon was available right off the bat, psi-capable troopers still needed considerable training (stat increase) to use even the basic powers with any reliability. With the implants, there may even be multiple levels as the technology improves, and also different implant types for different purposes (i.e. a psi-dampener for solders wanting protection instead). Effects could include Fear/Morale break, stunning effects, disarming (affecting nervous impulses enough to inhibit enemy accuracy or cause them to drop their weapon), illusion (enemy sees/fires at soldiers that aren't there) and, of course, mind control. If there are three or more abilities, different implants could exist which allow for certain bonuses (or restrictions in usage) of these abilities.
Okay, I'm getting a little carried away here...
Air support, if still under any consideration, could possibly be handled with the implementation of random-generated map elements/cells/sectors. When a ship is shot down, it's "damage level" is set to some value (say somewhere between 1 and 5, with 5 being cracked with some smoke, and 1 being nearly destroyed). When the player transport approaches the crash, they are given an "overview" of the crash status (a bit of text describing the crashed ship's damage level, possibly plus or minus one level) and the player is given the option to begin mission or fire on the ship first. Based upon the weapon mounted on the Transport, and the size/durability of the ship, some of the aliens may be killed, and the damage level may degrade one or more levels (the latter being more likely). Of course, a ripped-open ship provides the aliens less cover and more environmental hazards (fire, smoke), but greatly diminishes the recovered resources and technology for the player.
Just a thought, if the creation of multiple damage-level ship-crash map sectors is planned/isn't too big of a price for this functionality.
Whew, that wasn't so bad...