Ok, I'm not disagreeing with the point you're making here, but it really does irk me when you people continuously refer to a classical musical score as "generic Hollywood" fare.  Seriously...WTF does Hollywood have to do with orchestral music???  Some of you people have been around the internet too long.  Everything that isn't a trippy, jazzy, or quirky Japanese composed piece is "generic Hollywood garbage"? 
 Help me out here...
Look, I love traditional CV style music as much as any of the rest of you, but I fail to see what Hollywood had to do with LoS' style of musical score.  Last time I checked, orchestral musical pieces had been around way before the first motion picture ever got filmed.
/rant  
The difference between Hollywood and 'other orchestra' is the way it's written for the scenes and melds into the experience.
The problem is that LoS's soundtrack doesn't fit together with the gameplay in the way a game typically does. It tries to emulate movie style music flow, without the accompanying properly linked on screen visuals, because the visuals are controlled by the player.
LoS's soundtrack is written in a way that would work best as music closely knit with on screen visuals in a non interactive format. It tries to capture the Lord of the Rings feel in a different media without changing the flow to match the new media.
The tracks contain too many emotions in one for the most part. In movies this is exactly what you want, as emotions, reactions, scenes change in a scripted manner as the scene progresses. You want to have the soundtrack follow the visuals every second, changing as things happen. In a game, a track needs to help craft the overall mood of the area it is played in at all times. LoS failed to do this for most tracks, and that is why it falls short. You have instances in a stage where it is very soft, calm, and in some cases so soft you can't even hear it, while on screen you're jumping and escaping a collapsing platform and whip swinging to safety. Then later in the stage you're slowly shimmying along some wall segment. Slow and boring in the moment, but the music is playing this epic booming section. Again, a complete mismatch.
This idea is not impossible to obtain in a game though, and it has been done many times. Even as far back as Super Mario World on the SNES. Yes, an SNES game beat out a PS3 game at it's own musical mechanics.