Harsh but fair, I guess. Even though I enjoyed the game immensely I too did start seeing the cracks in the game - most notably the recurring plot themes from Uncharted 2 and the lack of significant character development in this particular outing.
It was way too tacit and 'alluded to' rather than clearly touched upon... prime offender being the relationship between Drake and Elena. I mean, all this talk of a ring and wearing the ring, and not wearing the ring... yet no mention of the significance of it! So are they married or what?! Way too vague for me.
I disagree that the series is past it;s sell by date though, I finished the game desperate for Uncharted 4 so bring it on Naughty Dog... Bring it on!