I wish the focus were on treatment and compassion rather than awareness. What I fear happening, and think we have already started taking steps towards, is normalizing mental illness to the point of carte blanche acceptance. I had depression for many years and still have my bad days, but I don't want to live/work in a society where you can use mental illness for excuses. The focus should always be on getting help and coping as best as you can.
What should become destigmatized is saying "I have condition X" or "I'm getting treatment for condition X and it's really helping", not "I did Y because I have condition X, my b".
I also think that while mental illness should be destigmatized, it's still ultimately a private matter. People should feel like they can get help and receive support, but there are a lot of good reasons to not share with family/friends/coworkers about your mental illness. If I had ever told my parents about being depressed they would have lost thousands of hours of sleep worrying about me, and would spend a lot of effort trying to help even though they really couldn't. I also don't want my boss or coworkers to know simply because I don't want to be held to a different standard / treated differently from others, nor do I want any failure of mine to perform or meet commitments to have the (implicit) excuse of mental illness.