I can't help but think, though: Even if this was all Palpatine's idea to begin with, would someone like Vader, who is portrayed so often as wanting to destroy the Emperor, not once think of actually using Galen to truly bring down Palpatine?
Although I can see what SW01 means by planting the seed of rebellion in him.
If the developers once again wish to show Vader as a total slave to the Emperor, however, I think they've really missed an opportunity to develop a character who is portrayed as utterly one-dimensional most of the time.
"Everything I tell you is a lie. Every question I ask you is a trick. You will find no truth in me."
―Vergere to Jacen Solo