The tonal problems are a result of two visions and a studio mandate. I'm pretty impressed with the final product even though it wasn't the best thing ever.
A peek into the offices of DC/Warner Bros after The Avengers:
"Alright men, Marvel made The Avengers, but we are coming off the incredible Dark Knight trilogy. If they have jokes - we have grit. Let's stop calling Superman by his name and Nolan-ise him."
Someone in that boardroom said, "Sir, we don't have Nolan directing this."
He was hurled out of the 126th floor soon after.
After Man Of Steel:
"Wasn't Nolan's grit what people wanted? Why is this movie divisive? And what is it with people cribbing about Superman destro....