It has always been the case that you need a strong defense to win in the playoffs. I would also favor upgrading the D over Sammy Watkins.
I'd prioritize run defence. We might lose Tru. But Joyner, RNC, Webster, and Johnson is not a bad secondary. Not amazing but passable. Our run defence is sub-par. And whenever Brockers goes down it is awful. Look at how Fournette is shredding Pittsburgh right now. Stopping the run is imperative.
Yeah, the talking heads keep saying it is becoming more about offense, yet every year its the defense that is the difference. Plus, as they do often say, defense travels.
Now, as I mentioned in another thread, I would add youth to the OL, but other than that it comes down to defense. Take a late draft pick and or some UDFAs to find a diamond in the rough at RB to add more juice at that position to back up Gurley, but overall need an elite physical secondary and better run D in the front 7.