To all the people saying "It worked for Fallout 3!" - What worked? All FO3 really did was switch from third-person to first person. The actual stuff you did in the game was pretty much the same - You explored a post-apocalyptic near future inspired by the Cold War era, rummaged through ruins, sifted through junk, explored an open world with a larger main plot always in the background.
On the other hand, this is a complete genre shift and I've yet to see anything linking this new "X-Com" game to the original ones. "Aliens attack Earth" is far too vague and until more details are released, I'll go ahead and assume the worst. That isn't to say it couldn't work, but it would have to at least retain the setting and the visual design, as well as many other elements.
The whole "FBI agent" thing doesn't bother me as much, since the game could be dealing with the pre-X-COM era, or the forming of X-Com when the Aliens were first discovered. You might start the game as an FBI agent, only to end up as an X-COM Commando.
What DOES bother me is that while the genre change might be acceptable, the change in the game's underlying paradigm will strip it of any semblance of X-Com soul. I'll elaborate:
The original X-Com games were pretty much Sandbox. There were almost no scripted events, you were given the World and some Cash and told to organize the defense of the planet. How you went about this was entirely up to you. Where you built your bases? How many? How specialized? Which research did you prioritize? Which weapons you used? Did you use tanks or loaded more infantry? Each game could develop differently as you acquire key items in a different order.
Now move this into the FPS genre. Go ahead, I dare you. And even if you succeed, ask yourself if such a game could be made, especially by a minor dev studio.
In the end, this will likely be a standard linear FPS game with maybe some X-Com enemies thrown into the mix. It might not suck, but it won't be an X-Com game...