I had not noticed it was NOT Nokogiri until your post! Certainly shows how we see what we expect to see. I must admit now, though, I am a little disappointed. I thought Nokogirl was a bitchen name. WTF is a giri? ;)
I can understand one of your concerns about Ruby and doing justice to the language, getting caught in re-factoring, etc. Actually, I think we all go through that with Ruby by its very nature. However, its expressiveness and meta strengths keep us. We all need to exercise a little self-discipline...
Rails may "seem" limited, but I don't think it is and coupled with Ruby, the sky's the limit. You can mix-out pretty much anything and there are many other libraries which meet needs and "roll right in".