There should not be any possibility of the player dying at the end of the MQ, because that has never been what TES has been about.
It's one of the things I disliked slightly about New Vegas. It closed doors on the player when he did things a certain way without ANY indication whatsoever. While that is realistic, I don't play video games because they're realistic. I play them because I want to enter this world and tell a story.
New Vegas Spoiler
Spoiler I sided with the NCR during the NV main quest, but I had previously taken Veronica with me to the Brotherhood Bunker and replaces McNamara with Hardin. I did not know that there was no peaceful resolution to get the Brotherhood back on my side. There was no RP option to let the Brotherhood survive if I wanted to continue working with the NCR. I did not like that one bit.
You can easily roleplay a character in Oblivion as the player exits the Imperial Prison, hating the world, joins the Thieves Guild and Dark Brotherhood, completes those questlines, gets remoreseful, completes Knights of the Nine, does FG and MG, does the MQ, does SI. If you don't feel your character wants to play that way, that's fine. But it's unfair to close doors without clearly warning people of the consequences.
In Morrowind, you CAN be the head of the Fighters Guild and Thieves Guild.
Spoiler Hell, the best possible ending for that conflict involves the player bribing Eydis Fire-Eye with the Bittercup. Even if you don't do that, by the time the player actually kills Fire-Eye, or kills Percius, or some such, he's advanced to the point that he's in the endgame for that faction and pretty much on rails. The doors aren't closed until it doesn't matter anyways. Naturally, killing off the Thieves Guild does close that door, but there is a way AROUND that ending, and it's pretty clearly marked either way.
Morrowind does have the Great Houses, but let's be frank, deep down at their core, there's nothing to be lost by doing only one. You get a fast-tracked part of the end of the MQ (assuming you do it early), a place to store your loot, etc. There is no strategic advantage to one over the other.
But Elder Scrolls has never been about ending the game after the Main Quest. That has never been a feature of any game since Daggerfall (Redguard and Battlespire and the Travels not counted, since they're spin-offs designed to tell a very specific story). A large part of the game is the factions, side quests, etc. It wouldn't be a good design decision.
And learn to write unbiased polls. If you have an opinion, express it, but don't belittle other people when they have opinions that are just as valid as yours. That's why they're called opinions. I'm sorry if my desire to have a perfect good ending is "irrational", and I'm sorry you can't RP past doors that are left open for people who don't want them closed. If you want a game that has consequences for every action, that's fine. There will never be a game that will truly pleases you. For example, in Dragon Age, you can't just say "screw it, I'm walking away, Ferelden can die". You CAN, it's just called not playing the game. Likewise, if you want to roleplay your death at the end of the Skyrim MQ, kill yourself once it's over and say you sacrificed yourself. That's fine and dandy. But don't try and impose your will on other people because you don't have the willpower to say "I don't think the Thieves Guild suits my current character, I'm just going to ignore it", and then belittle people when they don't agree with your opinion.