I really don't know of any upcoming RTS games to look forward to, unfortunately.
However, there is a slew of older titles to be had.
I miss the old days when we had so many great gaming studios making great RTS titles. Westwood Studios, Sierra Entertainment, Relic, Gas Powered Games, Microsoft Game Studios, Ensemble Studios, Vivendi Universal Games, Big Huge Games, Stainless Steel Studios, and probably more I'm missing.
I don't know how old you are and how far back you've been playing RTS games, but some of my favorite titles are:
Total Annihilation
Supreme Commander (1 and 2, with 1 + Forged Alliance expansion being the best. The multiplayer community is still very active
here)
Age of Empires (I, II, III, with II being the best)
Age of Mythology
Rise of Nations
Empire Earth (I and II)
Homeworld (1 and 2, with 2 being the best)
Command & Conquer (too many to list, but Red Alert was really the best [RA2 pretty good too], and Generals is a close second best. EA ruined the franchise, besides Generals)
Act of War: Direct Action (neat ideas and pretty fun, but never really gained much popularity)
Soldiers: Heroes of World War II (awesome unit control and realism)
Faces of War
Rise and Fall: Civilizations at War (interesting concept, controlling a hero unit in 3rd person)
Ground Control (I and II)
Empires: Dawn of the Modern World
That's what I can think of at the moment. And of course Starcraft is implied.
Thanks for the trip down memory lane.