Dungeons--> Open world NMs.

[Zkieve]

NMs are by definition rather shallow content. No matter how great the fight. It's still a "go there, kill the mob". That's why I definitely prefer dungeon, especially if story-based.

The only way I would be favorable to tiered dungeons would be by the completion of each dungeon dropping a "key" to everyone that participated (the Age of Conan way), and having other rewards (in the form of gear) that isn't made obsolete by the following dungeons.

That way the possibility of variating one's dungeon routine grow fast enough to avoid boredom, and "gearing" newer players to bring them up to par with the rest of the group/linkshell is relatively painless and still offers rewards to more veteran players that are past the first dungeons.

TL/DR: Make it a progression with the key, but encourage going back with the loot.
That way the effect of every dungeon on the availability of content is maximized.
Variation -> PROFIT!

Yea that would be great.
I dont think "tiered" dungeons in ffxi were to good for mid leve players, it was almost all end game wise, apart from some capped missions.(dont think BCNMs are tired dungeons/instances).

I seen before that after a certain level you "need " to go back to the "lower" leves dungeons to collect items , so you can go help--> while collecting your items.

This way the community its brought together.This is another aspect i didnt put on OP, but dungeons will bring the world back alive, especially if they are the "leve capped" or "exp(sp) progression" type of dungeons.