There are so many different songs in the book that you never actually see any of the words to, and when you do, trying to imagine what they sound like is damn near impossible. Its the same with LOTR...so many songs.
I cannot stand all the purists on the westeros.org boards who nitpick each and every trivial detail that is different from the books. Some people have no lives. One dude actually said the battle was rushed. It basically took the whole episode, how much more time could have been dedicated to it?
It was kind of rushed, as compared to the books, but for film, it has to be. You can't spend the same amount of time Martin does on each topic, or else we would still be staring at Ned Stark sitting in a cell awaiting his fate.