Before we finally learned who Jacob was, in my imagination I pictured him to be someone much like Captain Nemo. They do have similar personalities as far as we knew up to Season 5: reclusive, disliking the modern world, judgemental, with a peculiar wisdom of sorts that inspired devoted followers. Of course it would be totally unoriginal if TPTB did this, and I would not expect them too. I just enjoyed combining two of my favorite old fantasy movies ("20,000 Leagues Under The Sea", and "Mysterious Island") with the similar Lost story in my mind for a while.
And now we know that Jacob is actually two people! Well not really, but we got two for the price of one when Jacob was finally revealed, which added all kinds of confusion into the mix as far as who is telling whom to do what and for why, on the island. How about that, we were so intently trying to figure out who Jacob could be, and then they threw the Bad Twin at us too (sorry couldn't resist the reference). I pretty much dare TPTB to unwind this thing to my satisfaction by the end of Season 6, but I will bow to their artistic genius when they do.