In my opinion, losing the symphonic sounds doesn't make Ashes a lesser album for the reasons I have stated above. These days EVERYONE and their MOTHER are doing symphonic sounds. There are so many cliché bands flooding the metal scene.
I love World of Glass and all. But for a band as original as Tristania, I doubt they would go back to that path completely. Of course, some symphonic elements will still be there, that's in their roots. I'm more interested to see what sort of experiments and surprises will be in the next album.