Yes, but these are trivial and already doable. The difficult part would be adding all those features OXC was not intended to have, from dialogues to trade UI, map transitions and all the rest...
XCOM had a trade system since the beginning, it is just that you sold stuff on the global market, like an agency does. As a Microprose game, XCOM just goes at a very different scale from an RPG game, or even say Jagged Alliance, so RPG elements go into conflict with the idea of soldiers being expendable in the first place, as opposed to typical RPG, where characters interact on a local scale and are expected to reach the end of the game. Baldur's Gate did allowed for characters to die but it had some hacks where the newly recruited characters matched the level of the one the squad, and losing more than a few would have made game impossible, it also had the protagonist character, which could no be lost, which was really annoying. Icewind Dale had similar system, but the new characters started at level 1 and were basically useless, so the the feature was removed for the enhanced edition, meaning one had to reload on permadeath of a character, and these games were relatively forgiving since only a few enemies could permed a character. In Final Fantasy Tactics, losing a character wasn't such a disaster, since the game regularly filled the pool with the new ones with higher level, albeit with different abilities, and one could always grind a level 1 character to higher level, which was a kind of cheating, so everyone agreed that proper game should have a per chapter turn limit, so player wont have time to grind super soldiers, and there are even mods giving this turn limit.
So maybe XCOM missions can have a turn limit too? If player takes too long to salvage an UFO, it gets lost, because aliens got a backup, finished the repair or got evacuated by a larger ship? A terror mission can end because due to player taking too long the aliens were able to complete the objective. That will also force the player to advance, instead of cheesing the AI out. Like I seen one beating Terror from the Deep on superhuman by just skipping the turns till all aliens got killed by the fire of opportunity, or one player just side inside the ship, opening door to shot the aliens. Really tedious and super retarded way to play the game. Games like Panzer General had a turn limit for a reason...
