Before I switched my test box to PKGNG, I culled my installed packages using some scripts based on pkg_info. There doesn't seem to be any good reason why these scripts should now break: I'm sure the new pkg query could be shimmed to provide the same results in the same format without too much difficulty. Wouldn't such a shim eliminate one more small irritation for people making this transition? One script I used was depends.pl which does call pkg_info and no longer works. Maybe this isn't so common as pkg_cutleaves still works for listing leaf nodes.
Just a thought.
Just a thought.