[cpenner461]

I've never really thought about this per se, but the first thing that comes to mind is that if things are uneven, it's generally more like some beans are burned and/or some aren't roasted enough. Either of those scenarios are going to produce undesirable flavors. I think the more common way to capitalize on a variety and depth like you mention is to roast different types of beans separately and then mix them. That said, there's a lot of complexity and variety just in single bean (or, single origin) roasts, differing levels of roasting bring out different flavors.