Something that is a considerable difference between debris fields and asteroids is how damage is performed.
With asteroids, you have a 50/50 chance of taking damage when you run over them, and sometimes that is a crit.
With debris fields, you almost certainly won't take damage when flying through them...except 1/8 of the time, you take a crit.
Does it seem to anyone else that this really amps up the 'diceyness' of the game? That is - if you run over an asteroid, sure you still have the same odds of taking a crit as a debris field, but the whole 'running over an asteroid' this is GENERALLY a bad idea in any case. 50/50 chance of taking damage means you are making a risky maneuver, and it just might be extremely bad for you sometimes...but it is never a safe or good idea; doing something at 50/50 odds is really pushing your luck.
With a debris field, though, you are very nearly guaranteed to take no damage at all...I mean, 7/8 odds of escaping unscathed are pretty good odds. Of course, if you do take damage, it's very rough damage. Consider a pilot like Soontir - flying through a debris field, 7 times out of 8 he just gets better (focused) and no ill effect. 1 time out of 8, he gets crippled and potentially killed (having any prior damage at all paired with a 'direct hit')...
I dunno, I guess the mechanic of 'roll a dice and see if you lose the game on a 1/8 chance' just feels...more random than usual for X-Wing. Especially given how many pilots LIKE stress - 'roll a dice, 7/8 chance you improve your situation, 1/8 chance a possibly-game-ending event occurs'. VERY 'dicey', that!