I'm actually working on a project to get various statistics about heroes attributes, skills and items: Diabloz.com
The Simulations tab allows to compare your stuff with max stats, or legendary/set items.
Pretty dang impressive. It is very thorough and well laid out. I was pretty surprised to find my defensive stats on my Monk were almost all green, and the only red was STR :P . Damage was a bit off, but not red yet, so there's that.
Keep in mind that green/red is a simple indication which needs human interpretation.
Indeed, depending on your build, some low attribute values may be justified.
A good example would be the block % : if you don't play with a shield, you don't care about being under the average, and you might want to compare your character with similar ones only.