I agree most of those are boring. Gaeta has been a popular fan choice for some time, but I also agree his story has to become more complex.

Apollo could be a Cylon in a number of ways without dad (or mom) being one. The Final 5 are clearly very interested in Adama and had one of their number become his best friend right after the war. Doing a baby switch — or even embryo switch — hardly seems beyond their ability. And you know, Bamber doesn’t really look like Olmos. :-)

As for Baltar’s humanity — it’s becoming clearer and clearer, and the producers in fact have overtly said it several times, that the line between human and Cylon is going to become very blurry. I suspect it will vanish altogether, they are all artificial beings from earlier rounds of this cycle.

So the fact that Baltar is “so human” may be why he’s the #1 Cylon, not a barrier to it.