Expectations might be too high. Smartphones are starting to mature and plateau, like video game consoles have. The PS4 and Xbox One are nowhere close to the amount of advancement in graphics and features that the Dreamcast, original Xbox, or the N64 was for their time.
If you look at Android, their phones are also maturing. The S4 and S5 were welcomed updates, but not even close to being considered game changers.
Plus, Jobs was irreplaceable. He was able to motivate his teams to a degree Tim Cook is not. Tim Cook may be a competent manager, but he's not nearly as savvy with products, designs, and ideas as Jobs was. To believe that Jobs passing won't have a detrimental impact to Apple is wishful thinking.
I expect the typical improvement in cpu, ram, screen size, screen quality, improved Siri, some iOS tweaks, thinner, lighter, improved battery life. But nothing groundbreaking, or surprising.
If i'm wrong, that would be awesome.