I've played a mere two games of DQ, and many of you will discount anything else I say due to a small sample size, but I beg you to consider the following anyway.
I've seen 6 adventurers enter the dungeon, and the only person who survived was careful to avoid the Treasure Chamber, and left the dungeon with 30 gold coins after realizing that everyone else was going to die and exploring just 9 total rooms.
Let's forget the Catacombs for a moment, which I recommend, since by turn 4 in our last game, I had acquired both the Vampire (1 damage per turn for the rest of the game) and the Shade (who has a 1 in 36 chance of instantly killing you each turn you're in the inescapable Catacombs). I tried to play conservatively and died 8 times before the game ended with my being trapped in the dungeon a mere one square from the entrance, and as penniless as I'd begun. I was killed not once, but twice by an unforeseeable and unavoidable Swinging Blade, which forced me to roll a 4 or less on two dice (both of which were, of course, failed).
I would argue that the game is not just pointless to play without the Death Can Wait rule, but that it is actively offensive to one's sensibilities in that regard. My reasoning is that without this rule, as host of the game, I would have enjoyed the company of 3 friends over to my house, and within 10 minutes of a 2 hour game, I would have been eliminated. Playing as the monsters is, I would argue, unsatisfying, particularly after two (or three!) of the four players have been killed.
I want to give you a nearly-best case scenario, ignoring the deadly Catacombs, and assuming that every single dungeon tile faces the perfect direction, that you never encounter a trap, snag, hitch, chasm, or other obstacle, but also for mathematical purposes, discounting the corridors because they are effectively not usable spaces, in part because of their dreadful tendency to rotate.
If you want to search the treasure room just once, your game will run 21 turns long (barring a rare Corridors). Since the game will kill you on turn 24 or so, this is already cutting things extremely close. To demonstrate why it's nearly impossible, I've broken the Dungeon Rooms cards into separate categories to show why 21 perfect turns is somewhere between improbable and "blue moon."
14) Non-deadly cards (like "Empty" or Catacomb Entrance)
2) Good Treasure, won't kill you (woot!)
2) Is this really treasure? 50% bad result (bottle imp, unstable)
0) Shuffle (doesn't count as a card)
1) You're probably dead this is unavoidable "Swinging Blade"
2) You're hurt! (razorwings, crossfire)
1) Corridor Rotation (may result in an instant unavoidable character death)
4) You can't play anymore (cave-in, torch out, trapdoor)
3) Weak monsters (skeleton, sorcerer)
3) Awful monsters (demon, golem, troll)
16) Search another pile of cards... the other piles seem to be filled with Scorpions... (if we assume that the other piles have similar ratios, these can be mathematically discounted)
So on turn one, you have 18 "harmless" cards available, and 14 "harmful" cards available (below shuffle). For the first ten rounds, you also have a chance of drawing an "instant-death" tile. Ignoring search cards, you are in a statistically likely to encounter 8 or the 14 harmful cards.
Now, just for fun, pick 8 of the cards below Shuffle at random. Encounter them in a row. Did your character survive? Now add to the fact that Torch Is Out can cost you 3+ turns (causing you to be locked in the dungeon and killed, since you only had a 3-turn leeway in your perfect run anyway). Also add Trap Rooms, Chambers of Darkness, Spider Webs, Chasms, and the Bottomless Pit... and how likely is it that anyone survives? In a 4-player game, maybe one person?
I know that better runs will happen, but I have some suggestions for ways in which death can be maintained, but made somewhat less inevitable. This would be rules to replace the "Death Can Wait" rule.
First: Add 10 to each character's life total.
Second: Instead of moving the sun each turn, the first player rolls a die and only moves the sun on a 2+
Third: Any effect that would kill you outright (rather than by damage), instead deals half your remaining life total (rounded up) and moves you if necessary
Fourth: Whenever rolling an attribute check, you may choose to use 1d4 and 1d6 rather than 2d6
... or.... you could die on turn 3 and watch your friends play a game for several hours.