Well at the current rate of development, it feels like the game is (at a minimum) at least another year off. It's taken more than a year just to flesh out the TEC, so if it takes a years per faction then that would be another two years to go (assuming they release the Vasari this fall as scheduled).
I honestly look forward to it as well, this game is already looking like it will surpass the original Sins in virtually every way, and I have almost 2,000 hours played on it since release back in 2008 (though much of that time was spent on mods too).
