Do their heads usually get nicer looking as they mature?
Sometimes they just "grown into their heads"- you know? A good bridle can help. I don't mean expensive per-se. I mean perhaps a tad wider noseband, sometimes a D ring vs a full cheek (with keepers), or vice versa, can make a difference.
Think of it like earrings. Some flatter your face with your hair pulled back, some-not so much.
We have one w/ a so-so head and a big blaze that falls to both sides. He looks smashing in a nice bridle and a a full cheek. His head is not-so-dishy. The D overwhelms him where the full cheek gives him a more streamlined look.
Oh- and I used to have one we showed, he had a gosh-awful head. I mean- just ugly. Now as an adult, his body fits his big head and he looks impressive. Still not a beauty queen but he fits together.