Re: Han Solo...(Possible Spoilers)
Alec Guiness did just fine in the original movie.
But he had five or six minutes screen time total in the next two films? It wouldn't have devastated the production if something happened he didn't or couldn't return.
"...the most elementary and valuable statement in science, the beginning of wisdom, is I do not know." - Lt. Commander Data, "Where Silence Has Lease"