There's still plenty of adventuring available within the 3i universe. The non-imperial sectors are ripe for adventures, as would be the Spinward Marches. It really just depends on what you are looking to do. There are still plenty of star systems with relatively low tech levels, not to mention that most canon "systems" are comprised of the primary planet itself, with no background for the rest of the system.
If you want combat there's always pirates. Or if you are playing naval actions, you have Aslan to the south, Sworld Worlds, Federation of Arden and Zho to the east, and Vargr to the north (galactic direction wise). I don't think anything within the 3I setting restricts you from having a grand adventure. Yes, it's nice for someone else to do all the writing and adventures, but the framework already exists for sector-spanning adventures! All it takes is some imagination and effort to put pen to paper.
If you want combat there's always pirates. Or if you are playing naval actions, you have Aslan to the south, Sworld Worlds, Federation of Arden and Zho to the east, and Vargr to the north (galactic direction wise). I don't think anything within the 3I setting restricts you from having a grand adventure. Yes, it's nice for someone else to do all the writing and adventures, but the framework already exists for sector-spanning adventures! All it takes is some imagination and effort to put pen to paper.