Opinions are like... well you know the rest
After 12 weeks of bonefishing over the last couple of decades I would have to say that my ideal line would be the one that casts in a controlled manner with good feedback no matter how much line I have out.
As you might imagine this says a lot about the rod too.
But on the topic of line, I would have to say that the taper should allow for short work in close, easy loading when you need to reach the average cast and a gradual back taper for aerializing a lot of line for those long casts.
I would say that the SH would have an advantage for long casts EXCEPT when you miss, the line is useless unless you strip back to the registration point at the back of the head.
A line with a gradual back taper let's you fudge with a sharp haul and get it all back in flight without too much strip adjustment, making the adjusted second shot which is typically better than the first if the fish did not spook.
For short work, I don't know. Shooting heads aren't known for gentle front tapers but they do load quick. I like the Rio Outbound on the flats, which is a 38ft "integrated shooting head".
The color change is a real plus. You always know where you are. However it's not as good as not caring, which a more gradual taper (e.g. a double taper) will afford. However a DT is crap for shooting line.
So IMHO the perfect bonefish line is a line with a gradual rear taper, a positive front taper that loads short, and of course if a gun for reaching out and touching a bone in it's tracks. The latter is the easiest characteristic to find, what's hard is the short game and the long line pickup for a second try.
I have used a line with an abrupt rear taper and hated it because I tend to maximize the distance I take the first shot to minimize their awareness of me. Because feeding bones don't swim straight I often take a smooth and single back second shot to adjust. This requires a long pick up with smooth continuous tension. I have to guess that a shooting head would not be right for me.