In the first poster they softened under the eyes and here they're emphasizing the darkness and grittiness

My guess is they're going for an older, more brooding, less naive Will - they're going to let the character's looks catch up in age more with the actor's.

On the arrrrr post, someone pointed out these may be fake posters Disney is circulating to throw off the fans so as not to leak too many spoilers ahead of time. I don't know that I've seen that done before - then again, for that reason, it *could* be true. Sort of guerilla marketing, stirring up the old fans without giving too much away too early ...