I would have assured first off that "El Dorado" was a Smith/Dickinson contribution as, melodically, it sounds a lot like something off Bruce's solo career (it has Skunkworks written all over it, as you have already suggested) and the heavy riffing is more in the vein of something Adrian would do. But, as Blitzkrieg noted earlier, the lyrics written in first-person are not very characteristic of Bruce so, and having read the whole press release, I wouldn't be surprised if this was a Smith/Dickinson/Harris colaboration.
With that said, I'm quite excited about the new album but, although El Dorado is not a bad track at all, I still wouldn't change it for any of the ones on AMOLAD. I'm not sure if I like the way the song progresses throughout its almost seven minutes. It's not that the different parts don't blend in together well, but it does seem to me that it tries to be as structurally complex as tracks like Benjamin Breeg from AMOLAD but ends up relying way too much on melody and, therefore, sounding a little bit monotonous. Don't you have the feeling that this could/should be a much shorter song, as in, a typical straight rocking Maiden album opener?
Anyway, just a non-musician's two cents here, hoping the song will grow on him and have the opportunity to enjoy "The Final Frontier" as much as he is still enjoying AMOLAD!
