Science was awful, episode framing was really quite offensive for a lot of people (though unintentionally so, it was still sufficiently obvious someone should've picked it up).
The pacing, acting, etc were all good; they just needed to edit about 20 lines of dialogue to rephrase the dilemma. Not least because Clara morally made the WRONG CHOICE, given the way they phrased the problem. The life of a foetus is not worth more than the lives of millions of humans. Even if the foetus is a moon dragon.
To repost what I put on FB it would've been very possible, within the framework of the story, to fix most of these problems just by framing it differently.
- Crazy moon shenanigans observed on earth (Same)
- They send up astronauts, with bombs just in case (Same)
- The moon is an egg (same)
- Actually it hatching won't make bigger tides (once it's gone the tides will be smaller, so leaving the mass there and killing it would actually have kept the tides excessively big), and the shell, being so much lighter than the creature, should have gravitationally stuck to it anyway to begin with. So in a slightly more sensible version humanity isn't much at threat from this except possibly from longer term climatic destabilisations.
- The earth government decide to blow up the creature ANYWAY in case it's going to come down and eat humanity or some such. And the Doctor buggers off and various scientists argue either way and dilemma again.
- And voila, instead of "is it OK to kill a foetus to save humanity" (yes), we have "is it OK to assume a newborn baby is going to be evil when we don't even know its species" (no), and thus you have the same dilemma problem where Clara's decision makes a lot more sense.
But as it was, the episode just had severe problems. Still marginally better than The Caretaker, but second weakest of the series IMO.