Yeah, I think it just depends on the fighter. Some fighters are good with maui thai, others with BJJ, others with wrestling, others to boxing. To each his own!
Exactly, that's the beauty of MMA!
The reason boxing is not used, is because those who are good at it, generally stick to boxing as it's the only style where you can do it as a pure form and earn good $$$$.
It's about time a guy like Frankie Edgar came along, who employs a lot of the subtle skills a good boxer does, including counter punching, angles and combination punching and does them well. You don't need power if you can employ these things, which is where the sweet science comes in. Not many understand it unfortunately, but hopefully he will be the first in a line of well rounded MMA fighters (not boxers) who will bring this to the table!