OK. Let's do this a little bit more civilized and scientific. BV
What exactly is BS, shmup-wise? Is BS something that is unfair? Is it something that merely feels unfair? Is it bad design in general? Is it something else entirely?
In my opinion, a given stage portion or boss pattern is BS if the difficulty can, through sheer bad luck, occasionally spike way higher than it has a right to be for its spot in the game, which for lunatic mode usually implies nigh- or actual impossibility with human reflexes. Patterns that occasionally throw impenetrable walls at the player are the most obvious offenders here.
Note that a certain degree of randomness (and thus a slightly variable difficulty) is to be expected for a card. Por ejemplo, VoWG can throw both easy and difficult waves at you, but they are never impossible or too difficult for the final card of a lunatic mode, and the total number of waves is high enough to even out the overall difficulty.
Something that can (and possibly has to) be 100% micromemorized from beginning to end is fair if the execution is humanly possible, but it is still boring and bad design nontheless. For reference, see Hourai Jewel.
Stuff like bullets with a hitbox/sprite proportion of greater than 1, as seen in SoEW, are just plain bad design. They are not BS as long as they are not used in a BS pattern. It is kind of more like a dog turd...