It's a lot of tricky work from an antler Andy, antler is hard to work with.
Willow is easier of course, but not as loud. Antler would be stronger
I'm sure an antler whistle maybe be very novel to some, so I see your point as to why some one might want to make one Andy.
Personally I would buy one, however I never use one now, as I don't get that remote, and I don't work dogs any more.not that you would use the same whistle anyway
But like I said I do see the point from an artistic angle, it just depends on if one has the skill and know how.