The Shoot recently interviewed former Smackdown lead writer Alex Greenfield. You can check out the full 45 minute interview at this link (it starts at the 15 minute mark), here are some highlights:
Earning Undertaker's respect:
"Undertaker, even more so than Vince [McMahon] was tougher to get to know. He is a man who is absolutely protective of that character. I remember when I got promoted to head writer, I was sitting at home making a list of "s--t Alex needs to do to make this work" and near the top of that list was I need to call the Undertaker and say, "I'm here to earn your respect." Because you operate with different talent in different ways and there was no shortcut with the Undertaker. You know that Eddie [Guerrero] and JBL liked me wasn't going to wasn't going to get me over with him cause he was a guy who's respect you earned."
Undertaker making the call to end the streak:
"There is no pressure that is put on the Undertaker to drop the streak. This was the Undertaker's decision, I have no doubt about that in my mind about that whatsoever. Nobody, including Vince [McMahon] is going to go to the Undertaker and say anything other than, "do you want to end the streak?" There's never going to be a [Alex impersonates Vince here] "God damn pal, Undertaker it's over pal. You're dropping the streak tonight." That would never happen in a million years. He is, and I think it's safe to say, the most respected guy in the locker room. I suspect he went to Vince and said this is the year and Brock is the guy. Thinking about it from Taker's perspective as such of a fight fan as he is, if you're going to go down, going down to the guy who walked away from wrestling and became the UFC heavyweight champion would appeal to his ego."
How well Undertaker was in tune with his own character:
"He had very definitive ideas of what Undertaker would do and what Undertaker wouldn't do and made those things clear. And here's the thing, he was absolutely right. It was never about getting the character over in the traditional sense, it was an absolutely right impression of the best ways to tell stories with this character. Even when the character would lose. Even when Khali was beating the s--t out of him, Khali, Undertaker and the team working on that, we all listened to 'Taker because 'Taker even knew how to make the Undertaker lose the best possible way. He was never the guy who would say, "oh well, you know I gotta win." It's the classic thing of when a wrestler pitches creative it's usually, "give me the title, I want to win." That wasn't the Undertaker's deal at all. He is a man who very much understands the utility of losing at the right time."