What I've read in the reviews is that Killzone: Shadow Fall isn't a bad game, in fact it's a good step in the franchise, however, it doesn't add something new to the genre.
I truly think that Guerrilla should let the current Killzone storyline die right here, and start another one in a distant future. Then, the first thing they need to do in order to make an improvement in the series is to add more factions and locations.
Killzone: Mercenary was a good step with the introduction of a third faction, but we need even more. Now about locations, I think they need to expand the Universe of the series, not only Alpha Centauri, and take player to Earth, Mars (terraformed), and other estelar systems, like Sirius. Each planet would have a different goverment which means different factions, and different alliances.
