Not that I've heard. The only forthcoming things I am sure of is a new Black Coach for Death, and the new magic supplement, with a Purple Sun of Xereus miniature. There aren't any rumours about what the next faction might be.
However, it is Warhammer Fest this weekend, so we might see a reveal of something for Age of Sigmar.
If I do hear of anything that might interest Empire players - so Free Peoples, Collegiate Arcane, Devoted of Sigmar and Ironweld Arsenal, I'll mention it in the Empire section of the forum in all likelihood. While I hope, the Free Peoples might retain the puff and slash, who knows what they may look like in future. Some artwork still shows humans as we knew their last iteration of models. We seem to see as many new factions as we do updates and expansions of existing factions. At this rate, it may be inevitable that some factions get dropped. I would hope not for the Freeguilds, since they seem to be heavily mentioned in the background.