Newer iterations obviously have boosts in performance. Having two cores doesn't immediately mean you win - what if processes an application goes through are all interdependent on each other and the app is not coded very well for optimisation across two cores? A single, more powerful core will do much better to complete the task.
While I'm probably going to do the same thing and wait for Apollo devices, what do you want from a phone that requires dual-core? It's just an honest question, because I can guarantee you that if Qualcomm continues to develop single-core alongside dual and quad, the single will not struggle with majority of tasks that a user performs.
Gaming is the only one I can think of at this point of time. I understand that people value high-detail gaming and the ability to show their friends that their device is capable of doing such and such. Yet 2D titles are still so popular, and I don't know of any mobile developer who does wonders in both gameplay and graphics. Take IB2 - incredible graphics at the cost of a weak storyline.
For me, gaming catches up when the gameplay is on the level of last-gen consoles. The newer dual-cores can push out PS3-equivalent graphics, yet I haven't found a mobile game that rivals a PS2 title (and in most cases, a PS title).