I think it's not possible to write a bad Epiphany hymn. The feast comes ready-made with superbly beautiful imagery - most of all, the star - and the metaphors for the Christian life write themselves. This is a lovely example, a translation of a Welsh carol by the Rev. W. Lloyd. The Oxford Book of Carols has it with a tune by Canon Owen Jones, entitled 'Seren Bethlehem' ('The Star of Bethlehem').
Dark the night lay, wild and dreary
Moaned the wind by Melchior’s tower,
Sad the sage, while pondering weary
O’er the doom of Judah’s power:
When behold, the clouds are parted,
Westward, lo, a light gleams far!
Now his heart’s true quest has started,
For his eyes have seen the star.
Now, Lord Jesus, hear our calling,
Deep the darkness where we stray;
How shall we, mid boulders falling,
Know for thine the rough-hewn way?
Lo, a light shines down to guide us
Where thy saints and angels are!
Now we know thy love beside us,
For our eyes have seen the star.