The author states: "If only Vangelis had inserted some more comprehensive themes and orchestrated them better, Mythodea could have been a classic."
To my opinion that illustrates that he or she (referring to the author) misses the essence of what Vangelis' philosophy is all about: avoiding to choose the easy ways and patters in music. Ok, some of the used harmonies, sounds and melodic lines may sound familiar, but first of all I think it's Vangelis' right to re-use them, whenever this fits in the ideas he has at the specific moment of creation. After all many of the themes we find in Mythodea are part of the very particular 'sound of Vangelis'.
Secondly - and most importantly - I think that all composers/musicians who can make music that doesn't necessarily include 'comprehensive themes' are the real artists, making a difference.

Mr. or Mrs. Author: Mythodea IS a classic.