Brandon Sanderson
Elend comparing himself to Kelsier is a kind of theme for him in this book. I wanted Kelsier to leave a long, long shadow over these next two books.
A lot of people couldn't believe that I killed Kelsier, since he was such a ball of charisma, and the driving force for the first book. (A lot of others CAN believe it, but are rather annoyed at me for doing it.) However, I happen to like this book specifically because of Kelsier's absence.
He overshadowed everything when he was alive. Elend could never have developed as a character–and even Sazed and Vin would have had trouble–as long as Kelsier was there dominating everything. He was a character at the end of his arc–while the others are still only just beginning. It's so much more interesting if they have to do things without him.
Just part of Kelsier's arrogance, I guess. Both as a character in the book, and externally to it. He dominated so much that he had to go.