Dead is dead mode is a great idea... for a more polished game. As others have aluded to, there are far too many bugs in X3 for that mode to really be a satisfying way to play, because I'd guess 8 times out of 10 you'll die to some stupid bs collision even though you were being careful because the game is just buggy that way.
What's the fun in working your way up for weeks or months being hardcore careful just to run into an asteroid? It'd just make you wanna kill an Egosoft dev, so why go through all that angst? I'm a very good player that rarely dies, but I still can't see this working for X games because of the glitches.