Those who deny that the Holy Theotokos died are inventing, those who feel they are ‘free to believe’ she did not die are also inventing. The reasons are not clear but it is not based on the facts.
There is no western tradition that she did not actually die, there is western modern speculation that she did not die, but it is not traditional. It is just another example of a faction of believers hammering away at the Apostolic Faith, trumpeting their reason over the faith once handed down from the Apostles.
The Feast of the Dormition/Assumption originated in the east as a complete concept: the death and resurrection of the Holy Mother of God. It was imported into the west in this way. Without this historical record the west would not even know that the BVM had been assumed bodily into heaven, it forms a complete whole with the funeral and burial and the Apostolic witness and participation. The dogma of the Assumption depends upon the tradition that she had died and resurrected, Pope Pius XII acknowledges this debt in his bull Munificentissimus Deus.
Some people here are of the opinion that it does not matter, since the knowledge of the fact that she died is not salvific. This is true, the knowledge that Pope JohnXXIII died is also not salvific. The knowledge that Saint Catherine of Sienna died is also not salvific. However, as the community bubbles up new ideas that they would prefer to think, and these ideas spread and it affects the thinking of many other people, we are distorting the truth and twisting understanding.