40K is the best newish strategy game, I'd say... But nothing holds a candle to Starcraft still... And this is coming from someone who prefers medieval high fantasy any day of the week over sci-fi.
The problem, I believe, is that game companies are trying too hard to make complex war games, and the complexity just ruins the balance and the ability to actually just enjoy the game. I think, other than 40k, the last game that didn't try to overcomplicate things was Battle Realms.
Starcraft and Warcraft were and are still the best because they're challenging, but intuitive. There's not a ton of micromanaging going on, and you don't have to juggle 10 different resources like in games like AoE and the insanely complex space games.