If you want *my* opinion, which isn't worth the paper it's printed on, I would play with the scarred and interesting piece on the left. I would also consider laying the long root flat and making some sort of raft planting from it. That's hard to consider in 2d, there are so many factors, but if the leaves and branching of the tree would be reasonable in a raft (or clump) style, it's one thought.
Hope you get some more thoughts from people more equipped to see the potential. There are some mighty talented people here, when they aren't arguing about Life, the Universe, and Everything.
(Oh, about the taper....yes, bunjin lacks taper in a general sense but makes up for it in movement....and you still tend to have some small amount of taper from nebari to apex. As to reverse taper, hmmm....have to look again. Certainly the trunks can reverse themselves, or even have several changes in direction, but going from thick areas higher up to more narrow areas lower down, that seems an oddly distressing situation even for a bunjin. Do you have a particular tree or example in mind
)
Joanie