In the spirit of bringing the gameplay of X-Com into the gaming tech of the present, it would be neat if we could have replays.
Simple, turn-based replays would be great on their own, and would bring a lot to the table re: hey bro check out this amazing shot my guy just did, or for FRAPsing good missions. There's a step above this that would be even neater though, which is being able to play out the whole replay in quasi real-time.
If you've played Frozen Synapse, you should know what I'm talking about. If not, take a look at
Frozen Synapse is a turn-based tactics game, but the replays have a neat feature where you can watch each turn played out in real time, as you can see in the linked video. Having that kind of feature in Xenonauts would be very neat, as instead of single bursts of fire spread out over time, you could watch co-ordinated fire and movement as the whole turn plays out at once.
Just a thought.