I think it's probably wrong to assume that a qHD display will necessarily consume more overall power than a lower resolution.
It's true that a 960x540 display has 35% more pixels than a 800x480 one, and that therefore any CPU/GPU hardware playing with pixels will need to work around 35% harder and probably chew up correspondingly more battery.
But that is only true while pixels are actually being updated. If you're not currently running a game and you don't have animations or other screen updating constantly occurring, then the CPU/GPU won't be doing any display work at all.
Also I suspect (feel free to correct me!) that a display's static power consumption is based much more on its size, brightness, technology, and generation rather than the total number of pixels. So two 4.3" displays of identical technology differing only in resolution might have very similar power consumption -- and a pentile qHD may well be lower.
FWIW, the much hated pentile is supposed to have lower power and higher brightness. While maybe not attractive for color work, it might actually be a very good fit for people who use their phones largely as monochrome e-readers.
