George Lucas has said (If I am not mistaken) that Anakin lost some of his power when he was defeated by Obi-Wan Kenobi and slid into the lava. What are your estimates on how much power Anakin lost in becoming Darth Vader? We know he lost some speed, because the suit was probably heavy, but what about his power in the Force?
I don't think he lost any force power at least nothing shows the opposite. And if he did lose power then he wasn't even close to achieving his potential in Rots, because Vader although slower seems to be a lot more poewrful then Anakin is.
Nah. Makes sense. Vader was considerably weaker than Palpatine. That is why he needed Luke. That is why he never usurped Palpatine. That is why he died in the attempt to kill Palpatine.