SaGa games are very distinct. They are all pure turn-based RPGs, but they tend to have a lot of mechanics that you don't see in other RPGs. Prominent features include random stat ups at the end of battles based on your mid-battle actions, rather than traditional levels. Also, learning new attack skills via random chance mid-battle (based on a few different factors). For example, if you use a Double Slash skill, you might instead execute a Cross Slash attack, permanently learning Cross Slash. Combat also involves linking attacks from multiple characters together into combos.
Outside of battle, SaGa games are usually very nonlinear. Most of your time will be spent sidequesting. However, what enemies you fight are not based on location, but instead your Battle Rank, a value that increases as you fight more battles. So, they are designed around the idea that you will eventually get strong enough to fight the games' story bosses, no matter which side content you pursue.
SaGa games have a lot of non-traditional settings and set-ups. For example, SaGa Frontier was a game with seven different main characters you could choose from, each on whom had their own unique story, plot progression, and final boss, set in a world where the craziest sci-fi and fantasy settings collided at once. The cast consisted of a bard, a vampire girl, a robot built by an ancient civilization, a transforming superhero, a fashion model turned fugitive/rebel, a magic-using jerk who invades hell, and a monster re-enacting the plot of Dragon Ball. There were also more than a dozen side characters who could be recruited, including interplanetary policemen, the reanimated skeleton of a king, and an inhuman mad scientist who operates a back alley clinic.
Then you get a game like SaGa Frontier 2, which is set in a pure medieval fantasy setting that tells the story that crosses 60 years and three generations of heroes, with half of its story focused on a Game of Thrones-esque political battle, as various heroes and princes try to conquer a continent. Both games are very different, and highlight how varied and awesome the series can be. The SaGa series has a lot of different faces, but is rarely conventional.
I have no idea what to expect of this new entry, but I have high hopes for it.
