Well, we could talk about what aspects we'd like to see in the game.
Obviously, it needs to have both turn-based combat and base/global management aspects. They've already said we'll have destructible terrain, which is good. (And pretty much required to really be x-com)
I would like to have expendable individuals, like the original X-Com. Having actual specific characters with voices and whatnot can be fun, but I think that takes away from part of the core of X-Com. You're an elite team, yes, but you're also fighting a war against a superior force. You're going to lose people, and having a small roster of actual individuals doesn't really lend itself to that feeling.
Take Silent Storm, for example. It's a great game and a lot of fun, but if you lose a favorite character you're more likely to just restart. You also have a Main Character who the game resolves around. If he/she dies, that's it. You're also a small commando force doing specific missions with a specific storyline. You can't really lose a lot of battles and still progress. And, while it does a good job of mixing up the missions, you're still stuck on a fairly narrow storyline.
X-Com needs to be the opposite. You've got to be able to fight and lose some battles without feeling like you need to reload. It should be ok to have half your face wiped out during a terror mission. Sure, it sucks, but you can always get more guys. The game needs to be dynamic and different every time you play. Ideally, you'd have maps be randomly generated (or, even better, have the major cities actually look something like the real city with randomly generated regular maps). You need to be taking out Alien Bases and responding to a shifting geopolitical environment as the Aliens gain or lose presence in the world due to your actions.