Sedan models are losing their appeal as consumers seem to be more interested in hatchback, crossovers, and SUV right now. That might be the reason why the Subaru WRZ STi sales have been going down although some other people think that it might be because the Subaru paid no attention to what the customers wanted and failed to give them the Subaru WRX STi that they want.
Some people think that the right move for Subaru now will be to offer the Subaru WRX STi as a hatch. Hot hatch has been getting a lot of attention and this might help the WRX STi increase its sales number.
If Subaru does come out with a Subaru WRX STi hatchback model, the vehicle will be coming in to compete with models like the Volkswagen Golf R and Ford Focus RS. Of course, Subaru has never indicated that that is the route they plan to take in the future but should they consider it?