I don't completely agree with your second paragraph . What you are suggesting is a two way call..... If the player kicks at a ball and it falls its an offensive shot. if nothing falls its a defensive shot. It is the intent of a shot that defines an offensive or defensive shot ...not the result after the shot.
I viewed the video quite a while back....probably need a refresher course lol. Anyway the video stated that on particular shots such as kicks...banks etc you can judge the intent of the shot by how hard they hit it. If they hit it hard enough to possibly pocket a ball somewhere it would be an offensive shot...it they are hitting lightly just hoping to make contact and hit a rail it would be defense.
Sorry I wasn't clear. When I said "most of the kick shots I've seen in league play are just an attempt to hit a ball so your opponent doesn't get ball in hand, so those should be marked as defense", I meant that those particular kick shots should be marked as defense, not all kick shots.
If they make a ball attempting to play defense in any situation, you don't mark it as defense, so the intent doesn't matter in that scenario. It's deciding whether a kick is an honest/realistic attempt to make a ball that can be tough to call. My contention is that
most kick attempts at a ball that isn't hanging in a pocket are more about making a good hit, thereby
defending against giving up BIH, than they are about making the ball. That's usually true even at a higher skill levels; the difference is the degree of cue ball control.
At higher levels of play, you might be able to discern the intent of the shot by the speed in a lot of cases, but for lower skill levels, the speed usually has more to do with their lack of control or preferred kicking speed that it does with whether they are truly making an attempt to pocket a ball.
In any case, I'm not implying that it's illegal to consider wild kick shots offense; I'm just saying that my bar for an offensive shot is considerably higher than "it might go in somewhere".