in a perfect world, you never trade a player of his caliber.
but Anaheim is just about as far from perfect as you can get in baseball. It's an unnoticeable, indistinguished place in the middle of a vast suburban sprawl - even those of us who have lived here for years can't really tell when we've left Orange or Fullerton and entered Anaheim; it's forever in the shadow of Los Angeles & the Dodgers. The Angels have the worst depth of talent in the majors with no hope for improvement in the immediate future.
They've got Trout and little else. They have him under team control for 4 more seasons. As those years tick down and the losses pile up, the probability of losing him to free agency becomes a near certainty.
Is he being actively shopped? No. Should the Angels listen to any reasonable offer? I think they must and probably already have fielded one or two feelers.