So... what the hell IS Icarus?

We are almost 24 hours removed from the unveiling of Irrational Games's new piece of software. It is titled "BioShock Infinite", and it looks pretty damn good. 
There's a problem, though. 
I'm not sure why, but in the previous month I have been discussing theories with many Irrational fans over what direction their next title could take. We discussed sequel possibilities, new ground they could cover in narrative, or even genres. Of all the things we discussed, of all the game possibilities that crossed our mind, a sequel to BioShock was never once on the table. 
When I turned on my PC yesterday afternoon, I went to Giant Bomb to see what the new game from Irrational could be. I then read the headline "Irrational's new game BioShock Infinite". My heart sank a little, and my mouth kind of did this twitchy thing. 
Of all the possibilities my friends and I had theorized, of all the caveats we fathomed, we hadn't expected something so... predictable. 
Irrational Games makes very good games. In 2007 they released BioShock, which became a champion of sorts for the Games as Art discussion. With how final the last chapter seemed in BioShock, I was honestly taken aback by how out of left field the sequel's announcement felt. 
Irrational Games's next game was not supposed to be BioShock. It wasn't supposed to be SWAT 5 or System Shock 3, it was supposed to be something new, something daring, and something worthy of the mantle that Irrational Games has taken up since BioShock's release. While BioShock Infinite looks promising, it does not generate the excitement I felt when I played BioShock for the very first time, nor does it seem to have the same flare that made Rapture come alive. This leaves me wondering "why?" 
Irrational seems like a very talented studio. It is because of this--as well as seeing and hearing the imagination of the group--that I am struck dumb by this. Why is it a First Person Shooter with Light RPG Elements? Is this all Irrational can do? Or how about, why is it called BioShock Infinite? What is infinite about BioShock, or the narrative? Does it deal with infinity in some way? Probably most maddening of all, is what the hell is Icarus? 
These questions are moot, I suppose, since BioShock Infinite is not seeing a release until the year of 2012. At this point then--as a fan of BioShock and Irrational Games--I am left sitting here with no feeling one way or the other about BioShock Infinite. There's no anger or feeling of betrayal, no excitement or even feverish fanboy squeals. It's just... confusion with a slight shrug of the shoulder. 
I honestly expected Irrational's next title to blow me away. Turns out it couldn't even blow a balloon for me.