Wow. It amazes me that I totally disagree with most of you. When the rumours first started to circulate about the possible use of Khan as the villian I was really disappointed. I wanted my characters to encounter new situations, not retread the past.
However, Cumberbatch's performance totally won me over. Where TOS "told" me that Khan was a huge menace and an imminent threat, Cumberbatch showed
me that this was the case. I believed that he was capable of anything. I didn't have a feeling of dread when Montalban was on screen...I certainly did when Cumberbatch was.
As for backstory...I didn't feel it was necessary in this case. We were shown that Khan was concerned for his own people, and that he believed that they had all been wronged. He was going to act to correct the wrong. I didn''t need to know the whole story. He and his people could have been evil just because that was their nature...and I find that even scarier than than a full explaination.
For me, this Khan rocked.