[MENTION=23751]Maxperson[/MENTION], the fact that you and your group didn't play 4e doesn't respond to what I posted:
(1) It can't be true that, in D&D, it is unrealistc or (more unrealistic) for someone to survive a fireball, as that has been part of the game from the beginning;
(2) You've not articulated any reason why it the way the survival is determined at the table (by roll or by stipulation) should affect the degree of realism of the fiction;
(3) It can'be be true that, in D&D, only the GM can make decisions such as that a fireball doesn't kill someone - because in 4e a player can make that decision;
(4) If a player or GM, on any given occasion when they can make such a decision, thinks that survival would be unrealistic then they can make that call - which has happened on occasion in my 4e game.
This isn't abour preferences. This is about whether or not a particular mechanic affects
realism. You've given no reason why it should. And you make assertions about your game being more realistic than my game, but with no evidence - eg you have no idea what proportion of characters have survived fireballs in my game compared to in your game.
Which really goes back to the proposition at the heart of this thread: if
realism is about the properties of the fiction, there is no reason to think that GM-driven play increases that realism; and if
realism is about the process of producing the fiction, no reason has been given to suggest that
GM-decides is more realistic than any other method of authorship.