Announced at a Game Developers Conference talk by lead designer James Russel, Creative Assembly will be trying its hand at free-to-play gaming with Total War: Arena. Going in a slightly different direction, this new title is said to be entirely multiplayer-based and a mix of elements from real-time strategy and MOBA gameplay.
The press release mentions that players will "pitch history's greatest commanders and their armies against each other in massive team-based battles," suggesting that Arena won't be tied down to one specific historical period. At the aforementioned link you'll find sign-ups for an upcoming closed beta. I'm hopeful Creative Assembly can tackle F2P in a relatively consumer-friendly way, but failing that, we've still got Total War: Rome II to anticipate.