Faster silicon isn't really doing much for stock Android
Stick a Nexus 5 next to a Nexus 4. Sure, there's a slight improvement in performance here and there but we're talking very slight outside of benchmarks and very cpu heavy operations. For some reason the N5 seems to perform better when buffering new content in a large list (Google+, the Play store etc.) but both are buttery smooth throughout.
I can't help feel this plays a part in why some tech journalists are coming across as quite bored in their comments towards new devices.