please lock people to dungeons for 5 minutes

Getting a 30 min deserter debuff doesn't stop them, what makes you think they wont just AFK or teleport out of the dungeon instead?

Which means you will be stuck for 5 min, without a tank and no chance of replacing him.

This sums it up pretty well. Bottom line is we can’t force players to do things they don’t want to do, and why would we want to do that anyway? It’s a game; you should only do what entertains you.
Before anyone changes the topic to “yeah but we’re forced to do dailies”, I do understand that the game sometimes requires players to do things that they might not enjoy so much in order to be able to reach some things that they do.

Ideally I would like to see every aspect of the game to be as entertaining as possible to every single player, but there are 2 problems with that:

- One, everyone is different, different tastes turn this into an impossible task.
- Second, whenever you create different types of content, there will be people that will choose the content that seems to follow the path of least resistance towards an objective (example: gear).
So if you have two paths to gear, one fun, one tedious, if tedious is somewhat faster or easier than the fun path, some people will still take that route even if it goes completely against their preferences.

The trick here would be to make every kind of content that shares a similar objective to take the exact same amount of time and effort, now, not only that is highly utopic as sometimes players like the objective but don’t like the path, so they will take that path anyway to reach the objective that they do enjoy. The only solution to that would be something highly uninteresting and dull, which is make every path present the player with a choice from all the objectives that exist. But then everyone would only play and experience a very small portion of the game.

Personal experience: memorable things almost never derive from something that is fast and easy. That’s why players have so fond memories of vanilla, it took them ages to get gear from something like Naxx, and that in return, brings us feeling of value and worth to those moments, but I remember very clearly how frustrating it was for some players to be wiping for weeks/months and farm mats/gold for consumables for several hours every single day.
I’m sure that wasn’t the most entertaining experience for a lot of people, but it was for others. That allowed them to reach the objective they wanted, which was to kill an extremely hard boss and get his precious loot.
The game is always evolving and we keep trying to make the “paths” as entertaining as they can possibly be, but I don’t think there is a design that will fit with every single player’s tastes. For example, there are some that actually enjoyed that nonstop farming and wiping even then, and this is not just due to nostalgia, they did enjoy it during that time.

TL;DR - Wouldn't work. {◕ ◡ ◕}