I can’t see the actual abilities of anyone, including myself to a degree, so I have no problem believing there are no “objective” measures of obedience. We believe there are people who are not accountable at all (for anything they do), but I think we fail to accept that each and every one of us is not accountable to some degree in some ways – and that the Atonement covers that degree completely.
That might be the only objective measure of obedience in which I believe – that we are saved and redeemed from those things that are outside of our control, and that those things probably are far more extensive than most of us realize, so we are asked to do our best while holding onto hope and faith that our effort will be acceptable in the end.
One of the reasons I believe in the most expansive view of “Judge not, that ye be not judged” is that I believe seeking objective standards of obedience denies the Atonement in a real way – by assuming we can see as God sees and make judgments God has reserved solely for Himself.
I know some might say that we can be judged against our past - by how much we improve over time. I agree with that, generally speaking, but I would add the caveat that we all might have personal “thorns of the flesh” that never leave us and "ceilings" beyond which we can't progress in mortality. We can’t become discouraged and give up in those situations because of how we measure up to our past - or our desired future.
I think that’s the heart of the message of 2 Nephi 4 – and if people like Paul and Nephi can struggle with something (whatever it was for each of them), I am prone to cut myself and others a little slack as long as we keep trying.
One of the reasons I admire my own wife so much is that she keeps struggling valiantly to improve in a couple of areas that are brutally hard for her – when it would be so easy to throw her hands in the air and just say, “This is who I am. God made me this way. I’m going to quit trying to change, since I know he loves me regardless.”
The following can be and has been abused throughout history with regard to some things, but I believe the idea that, in some cases, we don’t need to measure ourselves against either our past or our hopes and expectations for the future is a wonderful principle of the Gospel and aspect of the Atonement.
My own standard is, “trying to do the best I can to recognize what I should do and then trying the best I can to do it – knowing I’m not even sure what really is in my own control but trusting that the Lord has paid for my transgressions and will forgive me of my sins as I strive to overcome them”. That’s not objective at all, but it’s how I try to measure my own efforts.