I think we'll always see a mix of Real Time Strategy and Real Time Tactics games, as they cater to slightly different markets. Strategies are more for the emperor/benevolent master of every aspect, and have a large focus on resources and micromanagement. On the other hand Tactics let you get to the battles faster, and act as a military General, with little to no focus on resource management (see World in Conflict)
I like both, but if I had to choose, I'd say that Tactics will become more popular, despite liking the micro management style better (Rise of Nations is still my all time favorite strategy)