One of the biggest problems the Dodgers had on defense (which was, overall, surprisingly solid) was turning double plays. They were woefully bad at doing that in 2016.
They finished last in the majors among second base (68) and shortstop (70) when it came to turning double plays. We know Corey Seager isn’t going anywhere, and the front office is resistant to moving him off shortstop yet, so the logical improvement has to come at second base.
But not only does there need to be a defensive upgrade at second base, improved offense there is also a must.