This has been suggested and discussed many, many times. And the fact is, that this rule change would change a slight first-player advantage into a huge second player advantage. The first player could no longer ever end the game with a win; he would have to always make sure he builds up a big enough lead first, and then end the game; hoping that the second player can't catch up. Whereas the second player can continue to play normal Dominion, and win simply by ending the game while 1 or more points ahead. It would be very unfair to the first player. The object of Dominion is not to get the highest score you can (and then hope that it is higher than your opponent's score). The object is to end the game while you are in the lead.
In Citadels the one closing has 4 points more.
That could be something. The one closing gets a bonus. Then you have however another turn.
This would be less unfair.
The one closing either wins or ties.
The other one, if doesn't get enough points to tie, loses.
If he goes even, or overtakes the opponent, it's a tie. That would be another solution.
This would change mecahnics, that is true, but in my opinion, for the better.
This would make me rethink about my idea to retire from dominion.
I doubt that you made your original post in the midst of anger, so I suspect that it's an issue that you thought about for a while. Which means that your decision to (at least temporarily) leave Dominion will not change . . . at least, for now.
Yes, you got all my points and for this I really thank you a lot.
I don't think I have to add more, but, I would like to see some game mechanics changed and that would surely be something.