Maybe it's just me but the ending was abrupt for a very good reason: You ARE Lee. So when Lee dies, you die. In both endings the game cuts to black at the moment of Lee's death. That's no coincidence. Death is abrupt.
I do have a big problem with the post-credits scene, though. Since I died in that room, there's no way the game should have shown me anything that Lee could not see. I can't remember a single moment throughout the game that was not from Lee's perspective, so why the ending?
And you (the OP) say you can't imagine a TV show ending so abruptly, then look up the ending to The Sopranos.
Not going to lie, I'm actually really excited about Treyarch's next effort because Black Ops was awesome, and my favourite Call of Duty game (and I've played them all). I used to consider them the B-squad to Infinity Ward, but no way after Black Ops. The currency system, balancing tweaks, and Wager matches made it one of my favourite games of this generation.
@iAmJohn: why don't you attempt to bail out Black Rock then? oh, wait... you're not so keen when it's YOUR money at risk. They made good games but at the end of the day publishers are for-profit businesses and if Black Rock failed to turn a profit 5 years in a row then the only logical thing for a businessman to do is shut them down or sell them off.
The final 2 hours of Fahrenheit/Indigo Prophecy are absolutely fucking bananas. B-A-N-A-N-A-S. It's perhaps the greatest story in a video game ever for about six hours and then BLAM. out of nowhere, it fucks it all up. Shame. Still an amazing and memorable game, though.
After the superb Black Ops -- with its balanced multiplayer, CoD Points system, and fantastic Wager Matches -- I'm very excited for Treyarch's next Call of Duty. I'm not particuarly excited about MW3, but I will certainly be getting it. Who would have thought Treyarch would make Infinity Ward near-redundant? I certainly didn't, but it happened with Black Ops. I'm also interested in seeing what Respawn Entertainment are cooking.