1. During the Northern Song Dynasty, after Zhou Bangyan's arrangement and standardization, the epigraph system was relatively perfect. Therefore, at this stage, as long as the content of epigrams is enriched, words can compete with poetry. At the same time, a large number of approvers have emerged. Prior to this, epigrams were only used to express feelings about home and country, but when they came to Su Shi's hands, they also became the way they used to say goodbye. This makes there is no difference between poetry and ci, which can be said to have opened up the north-south culture and promoted the integration of poetry and ci. Therefore, this process is also called the confluence of poems, and the main promoter is Su Shi. Therefore, people's evaluation of Su Shi's poem is not high, partly due to their own reasons.
Second, a large number of poetry appreciation should know how a person writes poetry, and understand his works in different periods. For example, a group of figures appeared in the early Song Dynasty, who were not as talented as Su Shi, but put forward the theory of poetic style rectification, which promoted the rise of Ouyang Xiu. Although their poems are not so incisive, their role in poetry is more important than that of Su Shi. Although you think Su Shi's poems are average, his level can rank second in the Song Dynasty. This has nothing to do with literary talent, but Su Shi's prose is really high, but because it is too scattered, other fields feel more successful.
Thirdly, some of Su Shi's well-known poems in the Tang and Song Dynasties are basically reasonable and have the characteristics of typical Song poetry. Due to the influence of the times, Su Shi's poems are at a disadvantage compared with those of the Tang Dynasty. Otherwise, how can you say Tang poetry and Song poetry?