When you send your Sith Apprentice to kill off the Separatist Leaders on a volcanic planet, you fully expect them to come home having taken care of the defenceless politicians without so much as a scratch adorning them.
Obviously, that isn't the case here as the recently corrupted Anakin Skywalker's wife turns up on Mustafar with high ground specialist Obi-Wan Kenobi in tow who hacks the newly dubbed Darth Vader into several pieces and leaves him to burn to death.
Emperor Palpatine, in the expanded media, apparently felt a disturbance before his apprentice was dissected and was en route to Mustafar quicker than you can say 'May the Force Be With You' but his medical cargo really boggles the mind...
Not only is his ship capable of replacing three (THREE!!) limbs in no time at all, Palpatine also has a conveniently designed breathing apparatus which filters air for badly scorched lungs. Add in the fact that Vader's body needs to be covered completely - OH WAIT - there's an outer shell of a suit, complete with cape, exactly in Skywalker's increased size.
Much more could've been done with how Vader got the suit - even a scene explaining a premonition on Palpatine's part would've done George.