Regarding the battery drain, that's a big premise but can we see the permanent touch of the screen has being as demanding on the IR detectors as a page turn?
Not long ago, the battery life was expressed in pages (something like 8,000 for the Sony 650). In that case, 4 hours of uninterrupted touch could be seen as 14,400 page turns (1 per second). If that were true, the battery would be low very fast.
TechniSol, fair point and I see what you mean
IMO, what is really wrong is that even after having triggered the sleep mode something can interfere and prevent the device from being completely sleeping (a cover, a paper, my light...). It's just a matter of seconds, but enough to be a bother.