To cut to the chase: Richard should have been Jacob.
After all, we already saw Richard off the island, with young Locke, and in helping get Juliet to the island. We already knew that Richard was immortal. We already saw how life-and-death significant Richard was in Ben's young life - at least twice (saving Ben's life after Sayid shot him, and helping Ben overthrow Dharma).
So what point was really served by introducing a brand new Jacob character - someone we have never seen before, making the rounds to see all the original 815 major players? Would not the Jacob character have been much stronger, more compelling, had he been revealed as someone we already knew - indeed, someone who we already had seen making the rounds with Locke?
Perhaps Richard will have a role in the final season which will justify his being overlooked as the perfect Jacob - but, for now, I'm thinking that Lost missed a golden, tingling opportunity.
See also Lost Season Five Finale: Jacob and Locke
5-min podcast review of Lost: Richard and Jacob
The Plot to Save Socrates
"a Da Vinci-esque thriller" - New York Daily News
"Sierra Waters is sexy as hell" - curled up with a good book
more about The Plot to Save Socrates...
Read the first chapter of The Plot to Save Socrates .... FREE!