I don't mind them going prog as long as they don't sound like one of the member's other bands. The problem of Open Up Your Eyes wasn't that it was prog, it was that it sounded like Transatlantic and that it wasn't a very good song.
On the other hand, songs like Blue Ocean, Infinite Fire and Cosmic Symphony also have a strong prog influence but do sound like Flying Colors and are much better songwise.
So, for me, they should go prog for some songs and leave the prog out for others, mixing it up like they had before. As long as it's an collaborative effort and not one member get's too strong a say, I think they will come up with another good blend of songs.