They need seven more to fill out the Fembot (2), Autobot (3), and Decepticon (2) sets already started in the early waves. This would leave room for another set if there is a wave 6, but not likely seeing as how they're skipping wave 6 for TR except for one figure that would have fit in the previous wave. They also would not need any additional torso characters, but we could get an extra like in CW. Piranacon is also unique with the extra swappable member for his weapon. The CW combiner formula can add the sixth member, but has to pick one specifically for that role. For that to be possible this set may need unique accessories that aren't made to work with the rest of the line.