I would like to see the Jetpack coming back. I wouldn't mind if they have another take on the Jetpack, like a water version of it (see Jetlev) or a Jetpack that flies horizontal instead of vertical (see Yves Rossy).
And dont forget jaguars and bears! Now with a better arsenal than John Marston I could finally take revenge on them. I hated it when jaguars and cougars came stealthy from the back basically killing me with one hit.