If there were 'only' the 50 new songs in the soundtrack, would you think it was too few?
It's not the matter of quantity, but of what was promised. Specifically, orchestrated music, not the one made on synthesizer. A good soundtrack may consist of even fewer than 20 tracks, but if they are memorable and of good quality then that trumps having hundreds of generic tunes. So, I don't want to bash anyone here, but maybe these old tracks weren't used before because of exactly this reason.
