Just wanted to add my two cents, as a dungeon generator was the main thing i was really hoping for when i first learned of LoG. Although I think AH have done a wonderful job with their hand made dungeon. So here are my a few of my thoughts, which i should mention are strongly influenced by my experience with playing Dungeon Hack.
The main complaint i've noticed against this idea is that the puzzles wont nearly be the same quality, and while I agree that is true, I don't really think puzzles are the main point of a random dungeon generator to begin with. A few people have suggested implementing pre made puzzles, that have variations, in to the generator might be one solution but I realise that might be asking a bit too much.
I think for a random dungeon generator type level, lock and key type puzzles would suffice. A few other variations are available too, such as walls that move when a hidden button is pressed, but by no means do these need to be complicated, well thought out puzzles like in LoG. They just need to be enough to encourage some exploration outside of "find the stair case down" and to break up killing monsters.
But rather than counter the few other points people have against the idea, i'd aslo like to make a few points myself on why a random dungeon generator can be a really good thing. First of all the nature of randomizing items (having both positive and negative attributes) within a random dungeon makes things interesting because constant exploration is not always rewarded but sometimes even penalised. What I mean is, in LoG i noticed it has ALWAYS been worth my while to explore more and find items, there is no trade off in terms of risking failure.
While on the other hand in a random dungeon, exploration could mean encountering monsters that I have no chance of defeating or finding an interesting item which is actually cursed or in some other way negative for my character. I find these sorts of gambles exciting and immersive, so while people might complain that these sort of dungeons don't make sense in the same way as a hand crafted ones, i find that's what makes them interesting
Hand crafted maps after a while start to become predictable and when they're not, it's because you're not following the designers 'sense' for the map and they can become quite frustrating. If we're talking about this being done in a "rogue like" fashion, there is no point where ones entire ability to enjoy the game can grind to a halt because they can't beat a monster or pass a puzzle, you can always start a new game and have a different adventure.
So while LoG is very much about solving puzzles and utilizing the items you do come across to the best of your advantage, a rogue like random dungeon would be more about taking risks and just fighting monsters untill you're either lucky enough to get to the end or you die, and this can be done over and over because the point isn't really to beat the game but to see how long you can survive (i'm imagining perma death with a random dungeon generator).
To sum it up, a random dungeon generator can't give the same experience as when you first played LoG over and over and it can't give you the same quality puzzles but it can make for an exciting game with massive replayability.
P.S.
It seems a lot of the people against this idea, are just more excited by the idea of hand crafted maps, which is fine, but i'm excited by random maps, random items and knowing i'm up against a challenge my characters probably wont survive. I really hope we get both