I think that, while Unicron Trilogy wasn't the worst invesment in term of marketing resarch, Energon and Cybertron Cartoons series were hated by older fans (Maybe not as much as most fan fated Beast Machines at first, but still.). Propably, returning to UT seems too risky for Hasbro and IDW. However, I think that nicely incorporated UT ideas inI wonder if it's in IDW interests to do something with the unicron trilogy
alligned continuity (Omega Lock and Star Saber in Prime, Demolishor in WFC) could be a hint, that this universe isn't entirely jossed.