I think Jake Lloyd deserves a second chance, but maybe through indie comedies or something like that. I'm not sure I'd want to see him in a Star Wars film.
As for the Vader rumor, nothing is impossible these days, but I find this to be a huuuuuuge stretch. Any note of finality in Return of the Jedi will be gone forever if Vader comes back.
Will we be forced to watch Hayden Christensen again? (Again, it was probably the direction more than the acting, but still, does anyone want to see a new Star Wars movie with Christensen in it?) If he's being brought back because he's the best villain possible, then what happened to his whole redemption in Jedi? Otherwise, will he and Luke be good buddies? None of it makes any sense.
Even bringing back Darth Maul, which was indeed cheesy, isn't as crazy as this idea. Darth Maul's fate is less directly tied to the saga of the six films. And, frankly, since Darth Maul was the only character that anyone liked in Phantom Menace (new or old), Lucas made a mistake in killing him anyway. I don't think anyone would say that Vader shouldn't have been killed in Jedi.
But I'm not really worried, because this sounds like a crazy rumor.