Firstly, as a lot of people know already, there were scenes involving Weyland as a younger man in the original script, which were cut. Ridley describes them in his commentary.
"I think you'd be disappointed that he's not showing himself as being the young man as well. I had every intention of seeing him as a younger man. On board a super yacht in the cyber Mediterranean, with a lot of cyber girls.
"Because if he was gonna say at 96 'if I'm going to go into cyber sleep and I can select that sleep, I may as well be at my prime, like, 42, with some super girls, having a jolly old time. I can do that for two and a half years.'
"In the scene, and it was a pretty good scene as it was written, he said 'This had better be good, because you've kind of woken me up. Do not disturb me again until you have something specific.'"
But it's more than that; Ridley thought Pearce was the best person to play the character.
"Self-made man, very highly educated, super high IQ. You know and British, therefore slightly well spoken, Queen's English, and I thought he's one of the best things in
The King's Speech
"The scene when he's going down the cellar for his champagne, with his brother walking behind him who will be king, it was great."
"I thought he captured that English aristocratic twang with a lisp brilliantly. He was good fun. It was great. Does his homework, knows his stuff. He's fantastic."