I really think Mayans are "built" for religion, but I agree, religion in G&K can and will often, with the right choice, propagate decent science accumulation.
Also I agree with "tall Korea" vs "wide Mayans". I haven't played a "wide Korea" and I don't think I want to. I'm not saying sit at 4 cities all game, of course. I haven't played a "tall Mayans" but I imagine I'd be losing the early benefit of 5 or 6 pyramids. Thing is, with "wide science Mayans" on higher difficulty you need to be isolated, else it takes quite a bit of shuffling to get that pyramid/library/monument in every city while you're trying to live.