I'm glad that he's going to be back for the next arc, mainly because I thought he was an interesting character and was disappointed to see him go in Treachery before doing anything.
That being said, I found the whole "resurrection" bit hard to swallow...from what little we saw of Walter's abilities in The Gunslinger, when he resurrected Nort, the guy was little more than a zombie. With James, it seems he's in full control of all of his facilities. That, and if Walter could resurrect him, why not Gabrielle whose corpse was probably 'fresher'? He says he couldn't bring her back, but there's no reason why...
He really shouldn't have been killed off to begin with.
On a related note...the backstory presented by Furth said that John Farson killed James' parents, and Walter was pitting the two against each other. Any chance we're going to see that?