God hasn't changed his standards. It is more likely that we have. If anything, I think he's become more compassionate towards us, at least he's not striking us down with lightening every time we sin :) I am grateful for forgiveness.
I agree with Godseeker that God is more compassionate now than he was in OT days. People commited polygamy back then and God was able to look past this sin and still see the good in that person. We should take this as an example and see the good in others first before we right them off and dame them to hell.
The Satandard, still remains the same, it is we who have changed, in the old days God dealt with some Sin immediately, in that People were struck down right where they stood. But now because of grace and calvary we can look up and ask for forgiveness and be pardoned.
I don't think God has become sympathetic, I think always new that we had a hard battle to fight ( Satan). This is why he has promised to leave us.
But we must never forget by thinking that God is more passionate that we will not be punished for our sins. The difference is in OT we we struck down immediately and now we have time (at least some) of us and Grace but we also have Judgement Day, ( Which is real).
I think back in the OT days, civilization and society was more limited, the use of language, writing, morality etc. was in a more basic form and God dealt with them on that basis - where direct action right in front of them was the most effective.
Today, we have the advantage of the knowledge of Jesus' life and sacrifice so don't have to work with patterns (sacrificial system of the OT), we also have a wealth of information available to us so our understanding of God's grace is more mature then is the OT (they also had the same grace available to them) and therefore God is dealing with us accordingly, we should learn from the experiences of the OT characters given to us in the form of the Holy Bible.