@bjorn

That's not really true... The stats aren't really on diminishing returns, the ratings that drive those stats are.

The question seems to be around how talents and racials that grant these stats play with these diminishing returns. "This tooltip says grants 2% crit per point and I have 15% crit right now- will I actually have 17% crit if I put one more point in this talent, or will I have something less?"

Things that increase the stats directly (usually talents and racials) are not subject to DR, while things that increase ratings (gear, gems, enchants, etc) are subject to the DR.

It's important to remember that DR applies to how much rating you have and not to the % you have. Whether you have 10% crit or 12% crit from talents, 200 more crit rating will give you the same benefit. What will drive the benefit from that crit rating down will be how much rating you already have. So, in answer to my on example question, if you have 15% crit, the talent that offers you 2% more crit will result in you having 17% crit.