In my opinion, this poem can be improved in this respect.
In this poem, I think this place can be strengthened.
I think this poem will be better if it is improved in this respect.
I think this part of the poem can be strengthened.
Using euphemistic language can help you to be polite and respectful when commenting on the shortcomings of poetry and avoid offending others. At the same time, it can also help the other party accept criticism and improve themselves from it.