[Update]: Paradox is stopping development on Imperator: Rome for the foreseeable future.
I must admit, it's quite impressive to see how much Paradox adores grand strategy games. They're already maintaining and updating four absolutely massive ones, but apparently that is not enough as they have just recently announced another grand strategy game, this time around set in ancient Rome!
Imperator: Rome has only just been announced so there aren't that many details available, but if you're wondering what it's going to be all about you should check out the Game Director Johan Anderssons PDXCon presentation down below. The video is both lengthy and informative, so I would definitely recommend you give it a look if you're interested:
If you're just looking for the short version, however, here's the brief description that came with the announcement: "Paradox Development Studio returns to ancient history with Imperator: Rome, a new title set around the growth of Roman power in a threatening Mediterranean. Unify Italy and then the world under the eagles of your legions. Or rule an Eastern monarchy with claims to the mantle of Alexander. Slaves, barbarians and war elephants bring the distant past to life in Imperator: Rome. Can you be a Caesar?"
That said, if you've played any of the previous Paradox grand strategy games I do believe you already know what Imperator: Rome is going to be about, as well as whether it's the type of game you'd personally enjoy or not. If you need a bit more information, however, you should keep an eye on the official website as I'm sure it's going to get quite a few updates once E3 rolls around.
And finally, allow me to leave you with the brief and fairly meaningless announcement trailer. At least it looks pretty!