Nice review, Chris. Even though I am most certainly a Nissan/Infiniti fan, the critques you leveled at this car (disjointed electric/gas integration, grabby brakes, relatively poor practicality) were described fairly.
I wonder about Infiniti's complete lack of priority when it comes to space/efficiency practicality in their vehicles. For a mid-large size luxury sedan (the biggest in the Infiniti lineup), that trunk is tiny. But I guess the other hybrid sedans are similar (Fusion, Altima, Camry, etc.), though as mentioned the regular M37 trunk isn't huge even without the battery back.
I found the same thing with my buddy's 2010 FX35 - beautiful interior, but the interior seemed very cramped and the cargo space was awful for a CUV of that size. Totally form over function. The G37 and EX35 don't have a lot of interior/cargo space either, but as smaller vehicles I seem to cut them more slack. I guess Infiniti thinks luxury buyers are more concerned with style/image than such mundane conerns as cargo capacity or interior volume - and they're probably right...