First, I'm still not convinced A15 is appropriate unless you add A7 in the mix. Like I said, battery life is just as important as compute performance IMO. In fact, I'd say it's more important once you hit a certain performance level.
Second, some (but not all) of Krait's advantages came from smaller process tech and higher clock speeds. However, we already knew the CPU there was 1.5 GHz, regardless of if it was A9 or something else. A9 at 1.5 GHz (your TI 4470) is not the fastest but it is no slouch either.
Third, I think the effective life of a smartphone really is about 2 years. Anything beyond that is a bonus. I don't buy phones with that kind of future proofing, but if that's going to be a consideration I'd argue that memory is probably more important. Despite this for some strange reason for the Nexus 7 for example people always talk about its 4-core CPU, without mentioning its 1 GB RAM limitation. Which is better future proofed in your opinion hardware wise, the BB10 with 2 GB RAM and dual-core CPU, or the Nexus 7 with 1 GB RAM and quad-core CPU?
It's analogous to computers. After you reach a certain point, the CPU is no longer the limiting factor. It's the memory. Indeed, I'm typing this on a G4 iBook right now. It generally works fine for basic AnandTech browsing, but every so often it slows to a crawl... because it runs out of memory and has to page out to disk.