If a roguelike does not follow its own rules, it ceases to be a roguelike, that's the thing.  Roguelikes are difficult, but they are a high _natural_ difficulty.  They are a system, and the process of beating them is learning and adapting to the system.  In this way, it is logical deduction that is being tested.

Not your luck with a pseudorandom number generator.

And this, ultimately is why a lot of games trying to be roguelikes fail at it.