That is not common sense, and plenty of successful stories have started 'in the middle of the book'. (actually most stories that are successful start at the most exciting point in someones life, and if the story/movie/book is successful, we then typically move backwards to learn how the characters got to that point, their 'backstory', prequel or origin.) But that is besides the point.
The story in a MMORPG is not the same as a story in a chapter book, or your favourite tv series. The story in a MMORPG is the adventures that YOU as a player experience while playing the game, using the overlaying world as a backdrop to set the stage to your adventures.
NPCs aren't suppose to view you as a protagonist, or some type of hero, but rather as another inhabitant of the world. The way that you PLAY THE GAME, and interact with the world and other players, is the story.
Sure maybe an NPC will tell you about some lost treasure buried beneath the Earth in some old ancient mine. But the story here isn't about you getting that treasure and returning it, the story is about how you explore the cave, deal with the monsters and ghosts, and even other humans you encounter on the way.
It would be even better if you could get to the treasure chest just to see it had already been looted before you. By another actual player. The story than arcs for you to figure out who beat you to it.
The story is a more organic experienced than a penned story, and is a reflection of what the players themselves do.
This is because in an MMORPG, we share the world with other players, so the story is similar to the story of our real lives, it is shared with other people, and is extremely influenced by who we encounter, and who has even come before us.
On your second point.
Not being strong enough for a quest is different than not being 'high enough'.
There have been plenty of games that I have played, that are online mmos, that will block off a quest or an area with a level door, or some other level-block mechanic, just for what is behind the door to have been WELL within my characters ability to handle.
To the point, that the monsters found behind the door were the SAME MONSTERS I FOUGHT TO GET THERE.
The door was not protecting me because I couldn't handle what was behind it, as I had already shown many times over that I could handle the content behind it, but rather the game designer, to artificially extend the length of the game, decided I had to waste X amount of time to get to X level to go on a quest that I was very much capable of handling before I had even hit that level.
If you really feel the need to show content chapter by chapter, and lock out the player from effecting the story, despite the human behind the players ability/skill level, intelligence, or cunningness, than maybe you should stick to writing books, making videos, or making single player games.
As for 'higher level players running you through content', this will occur no matter what, the level restriction only works to delay it.
In most cases, when running a lower level through content, it is to the detriment of the runner, they have to use much more supplies than normal, and take out time to do this.
Example 1 is back when higher levels could block demons for lower levels.
It would take the lower level an extreme amount of time to kill a demon, while the blocker had to use more potions than normal as well to deal with how much longer than normal it took the demon to be killed.
Instead, the quests should be structured in a manner that it is hard to even feasibly run lower levels through the content.
I will see PoI as an example, as it is a common quest that most of us understand, and it is frequently 'ran through'.
To be able to go through the content of PoI, it is of a massive detriment to the runners, they have to waste money on supplies, the extreme amount of time it takes to do the quest, AND make sure people that are coming along don't get themselves killed along the way.
Outside of personal friends, people are charged an amount of money to be ran through this quest.
Despite it being a paid service, and massive guilds running the quest, it is still extremely common for lower levels to die along the way.
But, even with all those checks involved there, people will still say 'It's unfair that they all get softboots in the end, they are just farming the quest'.
I would say the time, energy, risk, and money spent from the runners/blockers is enough to balance out the generation of new softboots, we could instead design the quest rewarding system differently it balance out 'farming'.
Instead of everyone being rewarded the same, we could make it so there is only one chest with the reward, and it worked like a normal chest, meaning there is only one item made. This is how demon helmet/eg quest used to work, before the update.
But people will say that is unfair, then I have another proposal.
Instead of it being a chest that everyone loots, instead there would be an angel statue that you could pray in front of, and if it determines to grant your prayer, you could get the reward. The statue could deny your prayer, and have a set amount of time before you could pray at the statue again. This is personally a way I would like to see quests done, as it gives reason for people to re-do the quest, and cuts down a bit on the farming.
You could also make sacrifices to the statue to increase your chances on getting the reward.
Farming quest items is only a problem on Tibia because items for the most part never disappear on Tibia. If Tibia had a durability system, quest items wouldn't become that common, and the farming of them wouldn't be as big of an issue. Though the reward giving system in the game would have to be designed around the fact that items don't last forever, and there would need to be ways to get items "more than once".
Lastly, and I really do mean this, game designers shouldn't be getting in the way of players playing together, despite the level difference, on an ONLINE GAME. The main point of playing an online game, and what makes them so great is that we get to play with other real human beings, and this should always be the focal point of these games. Locking off players from playing together typically has a big downside of turning away players from playing altogether.
