Yeah that whole presentation was pretty boring and JHH was not his usual charismatic self. I was also disappointed with the lack of info on tegra 4 over power consumption and gpu performance relative to the competition.
Well, that's a pretty straight answer in itself.
If they had groundbreaking 3D performance they would have showcased that instead of a useless webpage rendering test, which is heavily relying on software.
AnandTech showed how a dual-core Cortex-A15 eats up to 8 Watt (Exynos 5150) if it isn't restricted to a lower TDP.
Bog standard Cortex-A15 just isn't well-suited for mobile devices, hence the reason for Qualcomm's Krait and Apple's Swift.