Shepard is a legend and It's one of the damn things making this game as legendary as Shepard. (Warning: Spoilers)
Story was greatly improved but some of the elements of ME2 isn't that major impact. for instance the you'll decide if you'll destroy the collector base or preserve it. The only difference is that the Illusive Man will say if you destroyed it or not... no other impact that will affect your chances against the war or anything else.
Graphics was majorly different from the ME2 PS3. some people said PS3's ME2 is using ME3 graphics. I think not. look at the environment effect ME2 got no blurring effects just the Film grains.
Sounds got better too. although I liked the ME2's M-8 Avenger assault rifle sound better but it's still good. makes y'all want to spray bullets on the reapers.
The OST is, no offense didn't got better. it's just that. not bad nor good. I've noticed that most of the soundtracks that was used in the game came in ME1 and 2. like in ME1's OST is Vigil from the title screen. it was used in ME3 many times example when Legion is about to die the "Vigil" soundtrack played. in ME2's soundtrack "Overlord combat" came from the Game's DLC Project Overlord is used in the Mission Fuel Reactors when you team up with Captain Riley. also The Ending song titled "An End once and for All" got a slight hymn of ME1's "From the Wreckage" song.
I have to say the overall score is great. I'd give it 9.5
in addition. I've heard that other people wants the Ending changed but I think it isn't necessary. In my damn opinion the ending wasn't that satisfactory. What we really need is that we need more insight of what happened next. like What's the fate of the Turians, Krogans, Asari, Salarians, Quarian and the Geth. or How did they rebuilt their civilization? That is what we really need
The Ending isn't as Epic as ME2's but it's great .
Score Summary:
Graphics: 5
Sounds and OST: 4.5