And why cast Guy Pearce? He's a good actor, but unless they have some plan for a sequel, why not cast an old guy to play the old guy? He was not convincing as an old man.
Indeed. Lance Henrikson always seemed to be the de facto Weyland in the franchise and could have played the part adequately. Then again, AvP probably placed him way too early in the company history to be believable in Prometheus' future setting.