Your hymn has several graceful ideas, including the graceful descending pentad motif that appears in phrase 1 and 2. I think a few things are impeding the overall symmetry of the hymn.
1- Each phrase except for the last progresses to and concludes on a dominant chord, so to me the overall harmonic progression of the hymn circles for these three phrases.
2-The last phrase stands out, because it is harmonically interesting, but also because it lacks any of the rhythmic or melodic motifs in phrases 1-3 that would have connected it with what came before.
3- I would analyze the overall structure as A-A'-B-C. Perhaps it would be more balanced as A-B-C-A' or A-A'-B-A''
4-You have parallel 5ths in the second system, end of the 2nd full measure between "sweet" and "choirs". Perhaps solve this by utilizing an A maj chord (V/vi) on "sweet."
5-It would be nice to utilize the interesting rhythm of quarter note-half note, found in the first phrase m2 b1-3, again in phrase 2, and possibly in phrase 4 if you like the idea of an A-A'-B-A'' structure. Perhaps you could have an interesting ascending interval that grows taller each time. For instance, make "choirs" in phrase 2 an ascending 5th, F-C (quarter-half), and then speed up the rhythm in the latter part of the phrase.