The worst thing that could happen to the Impreza is to be a different line. This will allow Subaru to not over-engineer the Impreza to accommodate for the handling and horsepower of the WRX and permit Subaru to improve the WRX and STi for more performance oriented purposes. Looking forward to 2014.
I bought the Impreza because it was over-built. It's reliability is legendary and when it was new, it's standard feature list was very impressive, and IMO it had no rivals if one was looking for a practical/affordable/feature-filled/AWD hatch. Basically, it had every single thing I wanted in a car (and then some - AWD) and it was NOT a Corolla, Civic, Mazda3 - it was different and had character (not that those other cars don't, this was just different, to me anyway)
If/when it separates from the WRX/STI line, it will undoubtedly be because Fuji Heavy Industries wants to make the Impreza 'main-stream' and try to break out from their 'niche' brand image. IMO, making the Impreza more main-stream will likely mean generic looks, generic engine/powertrain options, pretty much generic everything. If this is the way they want to go, I'll not be re-upping with this brand as I refuse to be forced to get into a WRX to get what I want.