Brooke and Wilfred are two poets with opposing views, but it is important to notice that they both have something in common regarding their writing.

is it writing or writings

Well, that would depend on you! Writing = as a whole but writings = all the pieces of poems, etc. that they do.

Sra

I think both are correct.

However, I suggest you rewrite the sentence:

Brooke and Wilfred are two poets with opposing views, but it is important to notice that both poems have something in common.

In this sentence, the correct term to use would be "writing." The word "writing" is a gerund, which is a verb form that functions as a noun. In this case, it is used to refer to the act or process of creating written works. So, the sentence is stating that Brooke and Wilfred both share something in common when it comes to their act of writing.