You definetly have the feel down and faithful to the original but there are some things you can improve on.
1) Phrasing. Aside from the first phrase/verse/movement (or whatever you'd like to call it, I'll go with phrase) of the original song you don't bring the others into play until about 3/4 into the song, they need to be fleshed out more so you can at least do all of the phrases twice. Ideally I'd say use the main phrase a few times, then all of the phrases 2-3 times, and then end on the main phrase.
2) Variety. I definetly agree you just need more in the song, it's certainly clear you have an orchestral feel. The inclusions of a male chorus (as mentioned, like the original), stronger strings, woodwinds (ocarina-ish if possible), and stronger horns would be excellent and help to round it off with a solid dramatic feel. Heck, throw in a cymbal or two for dramatic effect. I do like the rolling drums on occasion which also serve as a good transition.
3) Progression. After you fix the phrasing you should bring in more instruments and more volume throughout the song, perhaps starting with the female chorus (main phrase a couple of times), then male chorus (all phrases 1st time), then strings and woodwinds (all phrases 2nd time), then horns (all phrases 3rd time), and ending with a grand finale (main phrase). Well that's how I'd do it.
If you were to take these points into account I think you'll have a real work of art.
And I like your latin title, Time Eternal, nice.