Structure: Sonnets are typically 14 lines long and have a specific rhyme scheme, such as ABAB CDCD EFEF GG or ABBA ABBA CDCDCD. Ballads, on the other hand, have a more flexible structure and can vary in length and rhyme scheme. The strict structure of the sonnet can be seen as more poetic because it requires a high level of craftsmanship to create a successful sonnet.
Language: Sonnets typically use elevated and ornate language, with a focus on imagery and figurative language. Ballads, on the other hand, often use simpler and more direct language, with a focus on storytelling. The use of complex and poetic language can be seen as more poetic because it creates a more intense and evocative experience for the reader.
Theme: Sonnets often explore complex and universal themes, such as love, death, and the nature of existence. Ballads, on the other hand, often focus on more specific and concrete themes, such as historical events, tragic love stories, or moral lessons. The exploration of complex and universal themes can be seen as more poetic because it allows the poem to resonate with a wider audience and to have a deeper impact on the reader.
Ultimately, the question of which form is more poetic is a matter of personal preference. Some readers may prefer the structured and elevated style of the sonnet, while others may prefer the more flexible and storytelling-oriented nature of the ballad. Both forms have their own unique strengths and weaknesses, and it is up to the individual reader to decide which they find more poetic.