I have two theories on why Moffat is as he is.

One is that he's just been too praised along his career so he refuses to take into account any criticisms of his work, regardless of validity, and has a little too much faith in his own talents.

The other theory is that he's just getting too old. I still think his first TV show, Press Gang, is legitimately one of the best British TV shows of all time. Sadly my knowledge of Moffat's career also makes me aware when he recycles himself. (He does it a fair bit.)