Orchestrated is good, but it isn't great. What matters is the melody. If the melody is good, it doesn't matter if you play it with a real flute or synth flute, it is going to sound good. What's best about orchestration and using real instruments are the human effects that can't be replecated (like hand drums for instance).
I made a thread awhile ago (like a year ago) about video game music. I also wanted music in games to be taken very seriously, for it does wonders to the end product. I gave an example, Requiem for a Dream I think. That movie was terribly sad all on it's own, but I think what really helped was the intense music and sad melodies. Also, look at Gladiator; the music helped me realize his fate. Same with The Rock. I know all of those are very good movies, but you can't say the soundtrack didn't help.
I think Mario 64 had that. Along with Zelda OOT....MM not as much, but WW had it too in some points (like the Forest Haven). This is off-topic but I loved the music that played in the flying levels in Mario, as well as that level with the eel and abandoned ship. Sunshine had to much tropical based music (I realize that it was based on a Tropical Island, but that was also one of it's flaws). Nintendo made Mario 64 perfect in my opinion. It was exactly what I wanted, a 3-D 2-D Mario. It had the worlds/levels I remember when playing something like SM 3 as well as many other new ones. [/off-topic]