Hans Zimmer knows his classics, there will, in this partition tunes that give an impression of "déjà vu". Wagner course through the few leitmotifs that run through the disc but this is the only thing that belongs to the great Richard Zimmer as the latter due to the very subtle and soft music when Zimmer emphasizes the respect for cinema. Bruckner also in the use of powerful winds, strings and rhythmic pulse (one thinks of the symphonies 7 and 9); Holst and finally with this brilliant cover of the theme of Mars in the "barbarian horde" (though softer and doleful performance compared to the terrifying execution made by certain phalanges orchestra with chopsticks as Levine).
All of the music of Zimmer can listen without reference to the film and the result is very good. It may be noted some shortcomings here and there which are related to technical writing for film (in particular the fact of not developing over time some topics - John Williams also has this wrong in Star Wars), but the result is Excellent as a whole.
A word about Lisa Gerard. I had the chance to listen live to the beginning of the career of Dead Can Dance and she already had this magical, captivating voice that takes guts. Time passed, the voice is rounded, with more inflections mezzo-soprano. It's a shame that it is embedded in the musical flow but the stamp is there, and it is very good. It is a pleasure to hear.
In summary, Gladiator, besides being a very good film, is also a VERY good musical score.