In my opinion (as a relative novice) if the management need to make the courses more difficult I think it should be weighted at the shorter ranges, it feels that recently everything is just getting smaller and further.
I am all for 15mm from 8 yards, as Simmo says its a game of finding your best compromise and we have enough long difficulty.
As for the short 15mm being all shot up if there are several across the course that evens the chances of getting onto one early, and if you shoot a series/league it should even out with time.
What about the typical scenario of a morning shoot with a sheltered wooded area and an open field area, as the wind generally picks up throughout the morning there is a distinct advantage to starting in the field, again this should even its self out over a a series?
I think there is a positive for course setters in having more small long shots - they are easier to set than that elevated, short, dark through a tiny gap mini kill