Originally Posted by Moriendor
Please remember that discovering some (hidden) paths/caves/dungeons required a party member with high perception to be the party leader. Many people might have missed this detail or had a party member that did not meet the reqs. Many people might have also not made it through the mountains in Star Trail due to a lack of appropriate equipment and/or party member's illnesses.
And finally there is a fair share of totally random encounters that some people might have simply missed out on due to the luck of the draw (or lack thereof).
There are many possible reasons why players might have missed out on some parts of the games.
These games are definitely not a play once, seen it all affair, not even for completionists since some content is dependent on being at the right place at the right time with the right party (or stat/skill set) and then some luck when the dice are rolling.