This may very well be the case, but indeed battery life seems to be improving over time. Yesterday's performance on mine was not great (although I didn't do anything special), then it was fully charged when I went to bed around 1:00 AM and 14 hours later I still have 60% of juice - the best performance so far.I think the reviews are a little unbalanced at times or that they are just using the watch bare bones with nothing running on it and not doing anything with it.
(AOD activated, no workout apps, heart monitoring on and just a slew of mail notifications in the last 7 hours)