While not mitigating most of the issues you listed, I thought I would mention the awesome https://github.com/ctran/annotate_models https://github.com/ctran/anno

While not mitigating most of the issues you listed, I thought I would mention the awesome https://github.com/ctran/annotate_models https://github.com/ctran/annotate_models plugin in case you did not know about it. I personally could not work on Rails without it. AR was born with a set of very opinionated decisions. I believe those that prefer a more declarative approach (and built-in identity map) can use DataMapper.