To be fair though, things like this are played with in almost every sci fi show/film that deals with time travel, including classic Dr Who. Most just see it as part of the fun of playing around with the concept of time travel, which seems to have many contradictions inherent to it. If we're talking real science, the concept of time travel itself is paradoxical in many, many ways so the whole of Dr Who is a plothole!
There's timey-wimey and then there's just sloppy, bad writing. Moffat just tries too hard to be clever at the expense of characterization and a good story. He's also a little bit too sensitive to fandom, often to the point of deliberately acting out to instigate a reaction. RTD was also too sensitive, but he went in the opposite direction of trying to please too many people.
All in all, I think seasons 1-3 were the absolute best of Doctor Who and then it went downhill from there.