If we get as huge an upgrade as the 4S was for 4 users, I'll be surprised.
But I doubt that. 4->4S doubled cellular bandwidth HSPA 7.1 to HSPA14.2. We're currently sitting with LTE at 100mbps, there is LTE-A at 150mbps, but no US carriers have it yet, and it's not a doubling, and there is no benefit to doubling. There are no real further gains for the foreseeable future for cellular speed.
4-4S. Doubled graphics, dual core GPU. The 5 is already so powerful, no apps are phased by even the 4S which will be 3 iPhone levels deep.
4-4S more than doubled CPU/number crunching ability. New generation micro-architecture in dual-core configuration doubled number crunching but also introduced multi-threading which was a huge boon. Again, the 4S and 5 are already so powerful no apps phase them.
These metrics will definitely not see such increases this time from the 5->5S as we saw from 4->4S.
4-4S, brought 5mp -> 8mp camera, plus new 5 element lens system and 1080P video. This may be significantly improved, 13MP? 8MP but larger pixels for better light? Dual flash with tungsten tuned flash for low light images.
4-4S, held constant with 10hrs of usage on battery. 5 held constant. Can they double battery life? Will we see a 5S that doubles the battery usage to 20 hours? That would be revolutionary... But I don't think we have that in battery technology.
... New major camera revolution. I don't see anything else, and if it does change, it will have little impact on the end users.