One of the Russians (Filatov?, maybe even Karjakin himself?) brown-nosed to the media that every match is 50-50 odds on the face of it...
But more seriously, Carlsen's rating has consistently been 2850 plus/minus a small amount (20) for some time now, while Karjakin has been more volatile, currently 2775 (near his career best 2788 of July 2011). So I think ...
8...f5 is no novelty. It is a well known line and has been played successfully before by strong players like Adams, Salov and Karjakin himself.
8...f5 is absolutely the correct move in the position, because it practically forces White to either surrender his strong central pawn on e5 or give up his strong light squared bishop for Black's knight on b4. I ...
The final position is a very typical position of weak bishop against strong knight.
The knight has good outposts on d5 and b5, where it is supported/protected by white pawns and cannot be challenged by any black pieces unless black sacrifices an exchange (rook for knight). Also the white knight is very mobile and can basically go wherever it wants.
The reason behind 25. Bh4 is very concrete, namely: With Rf8 coming next for black, white's bound to play Kg2 to unpin and cover f3 but without preparing it with Bh4 it leads to the following forcing variation:
[title "25. Kg2 without Bh4"]
[fen "r5k1/p5p1/2p1b2p/2b4P/5q2/5B2/P7/1R1QBK1R w - - 0 1"]
1. Kg2 Qg5+ 2. Bg3 Rd8 3. Qxd8+ Qxd8 4. Rb8 Bc8 5. Bg4 ...
Ah. I somehow missed that during live relay. Thanks for sharing.
Mikhail Tal comes to mind based on his Life and Games. He mentioned about 'forgetting' to stop his clock during tournament games for the sake of his time troubled opponents.
I don't know how many of us mere mortals could consider doing that. He must have been a jolly good fellow.
The pawn endgame is a draw. Black doesn't play h3 until white plays f4, for instance
[FEN "8/8/8/4p1k1/4P1Pp/5P2/3K4/8 w - - 0 1"]
3.Ke3 Kh6 4. f4 h3! 5. Kf3 exf4
If white doesn't play f4, then black only needs to be ready to answer Kh3 with Kg5, but that is never going to be a problem.
3...h3 is wrong. The key is 3...Kf6!
[FEN "8/8/5k2/4p3/4P1Pp/4KP2/8/8 w - - 2 4"]
White's king has to stay in the h-pawn's square, so it can't try to walk around the pawns.
Once white's king gets to h3, black should always be able to answer ...Kg5. If he does, then white's king can only retreat, unless he tries f4 there:
A few thoughts:
Leaving the king in the centre or long castle are not attractive either with all the open lines and pinned knight on c6
The g file is open but it is not easy for white to make use of it. White has exchanged its bishop which would have had a good square on h6. Also black's pawns on e6 and f6 cover important squares that could be occupied by ...
White wants to move his King to g2, but if he does so right away then Black can play ...Qg5+. By playing Bh4, White covers the g5-square, allowing his King to seek haven on g2.
Also, playing Bh4 activates the Bishop (it was extremely passive on e1), and allows White to connect his 3 major pieces after playing Kg2. Overall, just a great multi-purpose move in ...
OK, the only World Champion I can name for being jolly besides already mentioned Mikhail Tal is probably Vladimir Kramnik, who is always a pleasure to listen to in interviews, http://www.youtube.com/watch?v=mCURWc4tlYQ
If your counting the FIDE world champions then Ruslan Ponomariov springs to mind,
NOT world ...
Also with a queens side castle it would take the king two extra moves to get complete safety for the king and that would make black lose tempo and might lose the game especially when it's against carlsen.