I think that planning and packing could follow a three point approach:
  • best case scenario: plan and pack everything you are going to need
  • most likely case scenario: plan and try to pack everything you might need
  • reasonable worst case scenario: plan for it and pack according to your budget in money, bulk and weight

That approach allows to prioritize and have reasonable preparation. The proper packlist will be individual and varying over the seasons anyway. If your worst case scenario does not show the need for water filter, tarp and whet stone donīt pack it.
If it isnīt broken, it doesnīt have enough features yet.