"Don't be too proud of this technological terror you've constructed. The ability to destroy a planet is insignificant next to the power of the Force." - Darth Vader, A New Hope
One of the main critiques The Force Awakens has faced is that it is "un-original" and simply "remixes" the Original Trilogy. Nothing lends more credence to this critique than the existence --and then destruction--of Starkiller Base. Even I, a defender of the approach J.J. Abrams took, found myself feeling like this was a page from the old playbook while watching it unfold on the big screen.
However, after some time of reflection this is indeed a good thing. As Abrams has pointed out before, this movie was very much about going "backwards to go forwards." Aside from being a necessary step in order to win back those fans disaffected by the prequels -- on a storytelling level this very intentional step backwards was necessary in order to inoculate the new trilogy from falling into the trap of doing the very thing The Force Awakens is being accused of: re-hasing old stories. To even attempt writing-in a newer super weapon in future movies even more powerful than Starkiller would be silly at best, damning to the new trilogy at worst.
Assuming this is true, and I have no doubt it is, then what can we expect in the movies ahead now that Starkiller has joined the Death Stars in the superweapon junkyard of the beyond? Fundamentally Star Wars is about the struggle between good and evil, and in the Star Wars Universe that plays out via characters, their journey and the side of the Force they align with. But as Yoda said, and J.J. has hit on while trying to remain respectful of canon, is that the Force is everywhere and it was more mystical than scientific. The Empire wasn't evil because it owned a Death Star, and Luke's struggle wasn't to destroy a super weapon which was a tool of the Empire, but rather to sway his father from the grips of the Darkside.
As highlighted in the Darth Vader quote the Death Star was insignificant compared to the power of the Force, and I'm sure that line was not lost on Abrams/Kasdan while crafting the screenplay for this movie. Abrams has mentioned that he and Larry Kasdan knew the general beats of the trilogy and that this film is intended to set that up. With Starkiller out of the way early, the remainder of the trilogy can now focus on a way more compelling story that focuses on the mysteries of the Force and the choices our heroes and villains will have to face while gripping with it's pull. In the movies so far we've only seen a glimpse of what the Force can do --an even more interesting glimpse seeing the new powers displayed by Kylo Ren -- but surely nothing that would dwarf the destructive capacity of the Death Star.
Whether or not the Force is capable of destroying entire systems is possible or not, doesn't really matter. One can argue Vader's line can mean many different things. The point is that with the superweapon out of the way, we can feel relatively safe that we won't be seeing another one popping up in the remaining two movies, and my bet is that as detailed above, the focus will be more on the Force itself in the hands of the good and bad guys respectively.