After having pondered swapping my GS for a GO, and having gotten some advice from quite a few people, one common thing I picked up on was the size.
The GO is built for a larger guitar player whether intentional or not. It is deeper than a Dread, and longer as well, but shaped like a GA or a GS. Taylor is creating a trend I like, all of their guitars are the "Taylor" shape except their Dread (and it has some curve cues). The GC, GA, GS, and now GO are all the shape of a GA in differing sizes. Really cool concept when you thing about it.
With all that being said the GO will simply be to big for many players to handle for long periods of time. Its a lot of depth to drape your arm over (the perfect guitar for a bezel on a BTO).
I do not think it will displace the GS, but will pull buyers from other brands looking for a Jumbo sized guitar, or an alternative to a Dread.