They need, in no particular order:
-At least one more quality bat, at 1b/DH/OF, depending on where Bregman and Gurriel finally settle. Better yet if it's not another TTO type. The basic similarity of most of the lineup in approach/strengths/weaknesses made them prone to extended hot and cold streaks. No obvious help from within here... at this point it would be an unexpected bonus if Reed adds anything.
-At least two starting pitchers, especially ones who can credibly hold down the #3 or higher spot in the rotation. Right now the Astros have plenty of starting pitchers... the problem is they're all 4's and 5's. That includes McCullers and Keuchel, at least until we know the full extent of their health problems and any lasting effects. Fiers and Fister are perfectly fine... at #5. When they're at the top of your rotation is when they really suck. There are several people in the system who might end up as top of the rotation starters, but the problem is whether or not they are ready to do that next year.
- A left handed reliever and a closer. It remains to be seen if the future closer is already on the team or will have to come from somewhere else. Nobody seemed to want the job this year...
-Leadership, whether it comes from veteran players and/or the coaching staff. This was a team that seemed to be lost inside its own head much of the year. However 'unclutch' this team was, it was probably a matter of group dynamics rather than the fault of an individual(s)... so the problem will be very hard to diagnose and deal with effectively.
That's a hell of a lot to take care of in one offseason.