Dual-channel LPDDR2 is a step in the right direction for phones getting faster and faster. It's like going to dual or quad-core.
Except adding a dual or quad core processor has a significant impact on performance (and battery) as long as you have properly coded applications. Dual channel RAM, on the other hand, will only net you roughly 10-20% increase in performance for RAM limited cases (using data from dual channel RAM on desktops). In some cases, dual channel can be slower than single channel because it has higher timings. It remains to be seen if dual channel will even have an impact on a smartphone; loading massive photos into RAM for editing on a desktop takes a lot more power than loading part of a 10MB application into RAM on a smartphone. At the end of the day, we are left throwing around pointless facts.