Most often, this poem is looked at as an example of harsh discipline at best, and mild abuse at worse. To take the lighter side and assume that the relationship between the father and son is indeed loving, there are only a couple of clues from the text, which much be greatly stretched.
Diction means word choice. The title of the poem is called "My Papa's Waltz." A waltz is a lighthearted dance, and the poem suggests the dance is between him and his father. Ignoring the possibility of purposeful irony here, the fact that the son considers his relationship with his father like a dance, could imply a loving relationship. Also, he talks about the whiskey on his father's breath that could make a "small boy dizzy." Young children actually enjoy spinning around and becoming dizzy. When looked at in isolation, the strength of the smell of whiskey causing potential dizziness and the fact that the boy "hung on like death" could be a positive thing.
Also, the use of the word romped suggests playful wrestling.
The final line of the poem also presents some diction which could suggest a loving relationship.
Then waltzed me off to bed
Still clinging to your shirt
Being "waltzed off to bed" is actually a somewhat common figure of speech which is often presented in a loving manner. The boy is still "clinging" to his fathers shirt. If it was really abuse, would he not try to run and hide?
The entire tone of this poem comes across as lighthearted and dance like. The rhythm of the poem mimics the rhythm of a waltz. I do not, however, believe this is meant to mean that the relationship between the father and son in loving. Instead, I think it is done to give the false pretense of a loving relationship with a hidden dark side. The boy tells the story, after all, and what child is able to understand, let alone admit, that his father is an abusive drunk? If the speaker is looking back on this time from an adult perspective, he is most successful in showing the reality for what it was, but presenting how his childhood-self interpreted it at the time.