Usually the single should never be their best song anyway. I'm hoping the rest of the album will be different too.
It's funny, the first "new" Xandria album
Neverworld's End led with Valentine, which was the most powerful song on equally great album.
The next release,
Sacrificium, led off with Dreamkeeper. A good song, but not as amazing as the second release Nightfall, or any of several other tracks.
Maybe they wanted to really point up the new sound on NE, and I've grown to love Dreamkeeper, but wouldn't have led off with it at the time.
And Xandria is a good example as any, as they're more Nightwish than Nightwish nowadays.
I own both Anette/NW albums and they're great folk metal albums.