I just had a thought. Haki was introduced very suddenly and in the beginning it wasnt designed as we know it now, I mean, the body parts didnt turn all black, so the very concept of Haki was still designed parallel to the series. After the concept was finished, we could see Haki in almost all episodes after the timeskip. Now the awakening was introduced, so what do you guys think, can we except awakenings to become more often, just like Haki became?
Another thing that crossed my mind is that the Devil Fruit powers have appeared very recently in the One Piece world and if their users become more powerful and more proficient in using them as the time passes, maybe we will get to see more and more DF users with achieved awakening.
I know that what Mingo said about the rarity of awakenings opposes this, but maybe they are rare now, and as the time passes we might get to see more of them.
This is just my thinking, not my attitude.