The apostles struggled with most of the parables. I do not think that anyone these days, would have too much difficulty understanding the parables.
IMO.......in this day and age, nothing is more debatable or abstruse than some of Jesus parables. The same goes for some things that Paul said. For example: the specific identity of the trumpet of First Corinthians 15 (which was undoubtedly an OT trumpet, the nature of which was readily understood in Paul's day).......is a matter of endless debate in this day and age.