You can then have a few extremely difficult "elite" encounters that require significant skill. These can be for your relic weapons and whatnot. They give players something to aspire to without restricting the majority of the content to .
No, no no. Cause if you do this you get the balance problem you see in XI where all the new content is balanced against relic level weapon holders and people who want to play just once in awhile and aren't into 1000 hour grind super weapons are locked out of content.
Make high level weapons, sure, but make them reasonably accessible to all so that content can be properly balanced. Oherwise, the most hardcore get those weapons, then complain all the content is too easy and it messes up the game for everyone else.