" The lack of a roadmap might incline customers to look more favourably upon disk-to-disk (D2D) backup, especially deduplicating disk-to-disk backup. We can expect D2D arrays to be employing 4TB drives, possibly even 8TB ones, when LTO-6 tape drives appear in roughly three years time. Unless the LTO Consortium gets its ass in gear and presses its tape pedal to the metal, it could find that its lack of urgency will help bring about its own demise."
Yeah right tell that to the likes of CERN. Tape arrays and libraries exist and will still exist because they are more reliable, use a lot less electricty and tapes have a certified offsite shelf life (archiving / manditory data retention) of many years unlike HDDs. Unless that D2D is mirrored offsite you can forget any insurance cover for fire, flood and theft.
As for deduplication I am not sold as any large organisation and some small ones already emloy SANS that do that as part of their job. There is little to no value deduping at backup as the bigger issue is why all that duplicated material sat on far more expensive first line storage in the first place. Even the dreaded windows servers in 2008 / 2003R2 versions have deduplication capability in the storage server versions.