what do you think would disappoint him the most?
Hard to answer that question by pointing to a single issue, but if we broaden it a bit, I'd say that violations of the Ten Commandments that God had given Mankind even before the birth of Jesus in Bethlehem would be the key.
Time and again, Jesus took issue with violations of one or another of the Commandments during his public ministry. These deal with our personal behavior.
By comparison, he did not at all make the political situation or the natural environment or redistributing the wealth issues with him.
In short, Jesus Christ was about as far removed from today's Liberals as can be, even though they often try to claim him as a supporter or fellow traveler.