This difficulty/terrain discussion has been going on for ages!
They are not really very useful because of the numerous inaccurate gradings. A lot of cachers don’t even bother to check them before looking for the cache.
Some people find puzzles easy and others don’t so should the rating be set low if the cache owner is good at them or should they recognise that others will find them hard. Similarly caches up trees are easy for some and not for others. I like climbing trees so would tend to rate them way below 5 but others find them impossible. Some of our caches have been made easier by finders thus making a mockery of our rating
However most of us cache in a team of some sort and in most teams there is a good puzzle solver and a competent tree climber. In some cases the problem solver stays at home while the nutter goes out for the cache. Other teams even recruit extra members for specific caches. How can one possibly assess the D/T rating for a cache being sought by a team?
I have discussed this with Miss and she has over-ruled me but my suggestion was that we should re-rate all our caches at 1/1½. All our puzzles have at some stage been found after some help from us or by cachers who have been given the puzzle solution by others. Puzzle solution sharing is rife! Lots of cachers have claimed finds, and therefore filled in high terrain boxes in the grid, which they could not possibly have reached by themselves.
The laugh is that if we did that, some empty spaces would appear on some peoples grids!