So, at the risk of being a jerk, the original owner's "work" on these was at best conflicted, at worst neglectful. These aren't neagari (exposed root) style trees. That style has more order and some thought into root development and selection (and much more extensive) than what's been done here. There aren't enough exposed roots for neagari here. What's here is a mess of unpruned, unplanned roots that were likely exposed by soil eroding away and not being replaced. These should have been sorted out the first time they were potted up,
Continuing the path of the original owner will just give all those errors longevity. The worst thing is, it's entirely and pretty easily correctable. It's a matter of selecting the best plane of roots at the bottom and getting rid of the rest, covering what's left up so there is a decent nebari and selecting branching hard pruning it back to make more lateral branches. Alternatively, if you're set on neagari style, gradually expose more and more roots (they will have to be elongated in a taller container to continue much further) over time.
As things are now, these trees are in a "S%#@ or get off the pot" limbo. They're caught between styles and need some hard decisions. and BTW, wiring out branching on boxwoods is dicey. Hard pruning, cut and grow, is more effective.
Sorry, feel free to put me on ignore.