5. Freedom
One thing that cannot be stressed enough about Saints Row IV is how intensely it promotes freedom; this is a game where virtually no stone is left unturned in terms of mayhem. The dizzying number of ways you can go about any one mission makes this feel like the most fluid and accessible of the SR games to date, helping to keep it fresh and dynamic throughout. If you want to play old school and keep to the ground, that's fine, but if you want to fly through the air like Superman, open up some black holes and just laugh maniacally as everything is sucked up, then you can do that too.
This is the niche that Volition uses to differentiate itself from the impending GTA V; you can do whatever the Hell you want, as the game isn't really bound to telling a deep and nuanced story with the restrictions that it entails. This is GTA by way of Looney Tunes, and it is a game that categorically makes the player want to feel like anything is possible.