[Darvin]

Rather than rare occurrences (then it's even more up to chance) I would instead advise two things:

A) these occurrences are not a matter of if, but when and how many. That reduces the randomness somewhat by adding a larger sample in any given game.

B) any one occurrence is not enough to turn around the game, merely offer new opportunities. That way one bad occurrence at a bad time won't throw you off too much, but if you're unprepared for them on a regular basis it will.

Again, this is a balance issue. It's one that is particularly annoying, which is why I brought it up.