Happy birthday to the original Diamond and Pearl, by the way.
http://www.nintendoworldreport.com/news/58514/new-pokemon-legends-arceus-and-brilliant-diamondshining-pearl-trailers-released
On the 15th anniversary of Pokemon Diamond and Pearl's Japanese release, The Pokemon Company have dropped new trailers for the two Sinnoh-set games releasing in the next few months: Pokemon Legends: Arceus and Brilliant Diamond / Shining Pearl.
Legends Arceus will feature character customization and what appear to be boss battles against "noble Pokemon": the first Noble to be revealed is a Bug/Rock type called Kleavor that appears to be an ancient version of Scyther.
Pokemon Brilliant Diamond and Shining Pearl's trailer confirmed the presence of the Poketch, the smartwatch/multi function device tied to the bottom screen of the DS in the original Diamond and Pearl. A new function for BDSP is that the old Hidden Machine moves can be summoned from it; a follow-up tweet from the official Pokemon account confirmed that "wild Pokemon" use the move for you.