Latin is the most powerful natural language I know. The reason is that the grammar is so developed that the word order is essentially arbitrary, and that, together with other grammatical features, gives rise to a method I have not seen so fully realized in any other language: It allows you to express the content in such a way that the way you express it matches the content. For example, consider the verses: Daedalus…
My native Hungarian is also very powerful for poetry. It distinguishes between long and short vowels, allowing for close emulation of Greek and Roman poetry. Being agglutinative, it's also quite free in word order. Well, free is not the right word, because depending on the context and emphasis, only some orders are applicable. The point is, the word order carries higher level meaning, like intention and pragmatics instead of syntax.
There's also a huge amount of poetry written mostly in the 18th-20th centuries, but nobody except Hungarians can understand it so it's essentially unknown outside of Hungary.