I'm interested
I tested build 15913 and it seems they've fixed the :GetChildren() crash, can't reproduce it in any of the situations I used for previous build (it wasn't 100% reproducible, seemed to happen reliably when many nameplates spawned - ex. training all the mobs in Stockade).
Anyway, it seems the client no longer crashes with WorldFrame:GetChildren() so I reverted back to the 'traditional' way of finding plates as simpler.
Will keep an eye on this thread though for sure, an alternative is good to have.