Recently, I wanted to express the sentence "Maybe they'd make good pets." in Japanese. I initially tried to say it as such:
I was then corrected by a native speaker, and he told me that it would sound more natural if I expressed it this way:
Now, what exactly does this add to the sentence? I believe that in this case, なる is being used to mean "to become" (It's hard to tell for sure since I don't have a kanji for reference.) Was it added simply to make the expression more idiomatic, or is there a more grammatical reason behind it?