As someone who is a native English speaker, but close to native level in Portuguese (lived in Brazil for 8 years), I'm curious what you mean by English being less expressive -- I've never heard that before.
Both languages have their expressive poets, authors, etc. It's easier to rhyme in Portuguese (it's almost like cheating, since the verbs all end in the same syllables), it's easier to modify the grammar classes of words in English (turning nouns into verbs and vice-versa), they both have rich vocabulary (although English seems to give more multiple meanings to individual words, and have more synonyms too). But in the end, I'd never call either of them more expressive than the other...
Both languages have their expressive poets, authors, etc. It's easier to rhyme in Portuguese (it's almost like cheating, since the verbs all end in the same syllables), it's easier to modify the grammar classes of words in English (turning nouns into verbs and vice-versa), they both have rich vocabulary (although English seems to give more multiple meanings to individual words, and have more synonyms too). But in the end, I'd never call either of them more expressive than the other...