I'm going to re-iterate his point because you obviously don't understand what he is trying to say.
This is basically what he is saying:
Multiple small differences in middle of main story/quest --> Some minor differences in end which wouldn't effect a lot of people + one basic ending that stands for every different 'ending'
There could be minor impacts to things such as race, or preferred class, or quests taken that may make the middle of the quest-line different, you may do different quests or there might be differences in how different NPC's react to you, or which factions support you in your endeavors, but in the end it will still be the same ending. Lets take your example of playing an 'evil' character (which form the very start is flawed considering that a character cannot be evil and would in reality simply be working for what they perceive as the greater good, but nevertheless I will address it) lets say that your character is so 'evil' that he wants to join Mehrunes Dagon and the Mythic Dawn in destroying the world. As game developers, Todd and the rest of the guys will have a problem, which I will illustrate through the following made-up conversation:
Developer 1: Hey I have a great idea, lets make it so that the player can join the Mythic Dawn and help destroy the world!
Developer 2: I like the idea, but if we let the player destroy the world, how would we explain that the world still exists in the next game?
Now the developers could go in a number of different directions from here, check the spoiler tags to see the different outcomes of their future decisions...
Spoiler Decision 1:
Developer 1: Lets just say that only one of these endings is canon and ignore the other endings!
1 week after game release the forums, post, email and every other line of communication is spammed with the same message, you can't simply make different endings and ignore them. This is due to the very lore-strong presence in the TES community and it has been something that has distinguished TES games since Morrowind. As long as people think of this TES game one of the things that come to their mind was how they disliked how they ignored the variety of endings and used a quick-fix (Dragon Break), much like Daggerfall.
Spoiler Decision 2:
Developer 1: Well we could simply scrap the idea!
This is the safest decision, nothing was changed from previous TES games so it is relatively safe. There was little to no impact of this decision on the mass fan-base as a whole.
Spoiler Decision 3:
Developer 1: Well what if after the evil player helps Mehrunes, we bring it back to the original ending somehow, so there would be one canon ending to help continue the series!
Developer 2: So there would be different middles to the game, but only one real ending?
Developer 1: Exactly!
This is what me and most of the people saying no have been trying to say, this is a safe ending and will succeed in two things; one, it will allow the player to go through different paths so that their freedom is not limited, two, it will leave a single real ending with one actual outcome to the whole story. One of the biggest problems with this and the reason that people are still against this is that it takes a lot of actual work, its nice saying that we want this and we want that, but in the end there is someone who has to do all these things we ask before they actual become real, meaning we need to carefully consider whether these ideas are realistic or not.
Now a small personal response from me:
I noticed that somewhere you inquired to what
canon means, canon refers to what is accepted as lore-correct, a good example of problems with canon is the Star Wars series, where there are so many conflicting stories, books, games etc. that Lucas has to step in and say "Look, this is right, this is wrong, if you don't like it then deal with it." Which is a blunt and rather distasteful way to fix the problem.
@ Alex Man 142
Would you say that it is unfair that life forces you to breathe, drink water, sleep and eat and that it is shoving these things down your throat? Sometimes there is an inevitable that must be done, if the world is going to be destroyed by dragons there are only two real options, fight or run. Its not about them forcing you to do something, its about what would be possible and what would make sense.
That is a safe way to do things and I agree, giving the option of choice is good like in Morrowind where you could ask to join Dagoth Ur, but you couldn't because that would go against everything that the player character was, regardless of their actions within the game.
@ Jimis
You seem to be completely sure of what an RPG is, however I have yet to see how you would. An RPG is a role-playing game, it could be linear or it could be done sand-box style, it can force you down a certain path and it can open you up to various decisions, but rarely, no, never have I seen a game which allows for complete freedom in all of its decisions. Show me a game like this and I will submit to it being possible, however until then your idea is flawed in that it is simply not possible.
EDIT:
Lets not turn this thread into a language debate please, though I should note that when posting it was sometimes difficult to understand what you were trying to say Jimis, re-reading your posts and trying to help clarify them before-hand can go a long way in helping others understand you.