Okay. I confess: I haven't actually gotten to use the non-rock obstacles.
However, now that we've got a choice between Asteroids and Debris, it seems to me to be an impactful fleetbuilding decision.
Asteroids cause more damage when you land on or pass through them.
Asteroids prevent your ability to attack when you land on them.
Debris Fields cause a stress when you land on or pass through them.
Clearly, some fleets prefer facing some than others. Aggressors in particular find Debris to be a more favorable fight.
Also, having more shapes for obstruction might be beneficial in its own right: I could simply bring the 3 largest obstacles at my disposal to ensure a maximized Obstructrion rate for Biggs, or I could bring the 3 smallest to ensure my Shuttles don't get scuttled.
Anyone else have some musings as to this huge change in the game?