Well, Bullfrog Syndicate style!
Special one mission mode like BB1.
One player controls one soldier, selective 4-16 players map scaling with enemies.
Limited purchase of equipment, Laser Squad style.
Selectable missions - Laser Squad / selected XCom / BB1-BB2 could be used or recreated.
Can be implemented as “hot seat” easily, LAN and Internet via user hosting and client.
Not much, but can be interesting, if players keep the pace. Rick could be dead, if not careful.
I would love some co-op, it would make a promising game absolutely potentially extra-awesome but, alas, multiplayer wasn’t voted for enough during funding and as such isn’t currently covered by the scope of development 
I’m pretty much 100% against multi-player in this game, but I think a skirmish coop would be a compromise I could support. Being p2p would eliminate a lot of the cost in setting it up. I’d still rather wait to see it added as a mini-dlc though.
what should be bad about p2p? if it’s stable and fair it’ll be a huge blast! but co-op would be more interesting since controlling aliens is tempting but probably hard to optimize. since there will be different factions we’d have an interesting co-op campaign or versus already.
obviously SP is priority but a MP, even if trimmed down, could be huge since firaxis did not manage to get it right stable or working.
I think, given the playerbase drawn to this type of game, a large-scale strategic side-versus-side coop/pvp would be a great fit, though certainly a massive undertaking.
I somewhat disagree, given the lack of popularity in firaxcom’s multi-player. I think most of us turn based lovers look more to grand strategy games for pvp stuff. I can’t speak for anyone else, obviously, but squad level turn based stuff seems far more popular as a single player experience to me.
Edit: Not saying it’s entirely unwelcome, just that there’s better options for pvp. For my part, I’d rather all resources for this game go to the single player until release. And certainly, if there’s a lot of outcry for it, then go for it.
Large scale pvp campaign would be a niche inside the already niche-y turn based tactical game genre. One of the main issues with this is that not many players are able/willing to commit to a long campaign with a buddy. It’s the same with grand strategy games tbh.
+1
Exact reason why I mention BB2 style single battle maps. Purchasing equipment to balance players seen as early as in Laser Squad can be used.Its easy to implement, can work even as “hot seat” or LAN eliminating dependency on servers, or players can establish client and server connection.
well it has nearly zero players because it just does not work very well/stable
i guess one can look at MP of “chaos reborn” where they added a-sync gaming on top of SP
one option, but a working co-op and versus, even if trimmed down to the core and just another “extra” would be great! imagine those armadillo races we could have 
Perhaps if it were a persistent world with relevant factions. You could jump in and play one side of an impending conflict, or choose a conflict in which to play a certain side. For those who play MechWarrior Online, it’d be similar to their strategy-level approach to a fundamentally tactical game.