this tree is screaming cascade.
I believe you are correct....only....as a nursery plant.
As a bonsai, I think you'll find a better image using the trunk, and some of that new close growth to create something other than a cascade.
Mostly because you stand an excellent chance of finding something with one thick branch, that is already in better proportions to create a cascade.
The proportions of those cascading branches are such that, if you think about how long it took all of those undesign worthy branches to create that trunk, you can imagine how long it will take one of those branches to get to appropriate size to compliment the rest of the trunk.
To me, this spells a waste of this trunk and this trees best and fastest potential to create a pleasing image.
It won't hurt to leave one cascade branch on in the meantime, but I wouldn't remove too much of that other growth too quickly. This way your options are open. I'm quite sure though, that if you keep your eyes open for something faster to a well proportioned Cascade, you will find it.
Sorce