However, they should re-implement sneak attacks if an ally is threatening (or within five feet, the difference is negligible).
This is currently in the game, albeit it's a bit buggy at the moment.
The problem seems to be with the Size class of the creature- Minotaurs, Hook Horrors, Ogres and so on seem to not allow flanking to work because the models may be too big. Its not a rule problem but a bug. This problem seems to be exacerbated with Halflings.