I am actually surprised that there will be a new AC so soon after Origins. I don't think it will release in 2018 though but rather February or March, pitting it against RDR would be really dumb
Guessing it'll be a two year gap and release at the end of next year.
I still need to play Origins, and I saw a rumour that this was a sequel and you play as Bayek, which would be nice since I think the reason everyone likes Ezio the best is that we got to spend more time and learn more about him. Then again I won't really complain if it's a new person, either way Ancient Greece is pretty cool... not as cool as what everyone has wanted for ages, Fuedal Japan, but still cool.