Been using it in 1.12. Cool.

And I had an ideas or couple of them. As an alternative to lockpicking, but far more noisy, is to use a crowbar to force-open some chests. It will break the lock most of the times, but will get the things done. But it will also count the lock material, and likely blast resist. So it will, essentially, mean that locks with high blast resist will have far more resistance to breaching with crowbar.

Second suggestion is a thief mob of some sorts. Basically, either a villager copy or a player-like npc, which will try lockpicking your locks or doors, and will steal items from chests directly. But will drop them once killed and not despawn. It will have an AI config of running away from players and golems, but will have a neutral stance as in it will attack the attacker. For item taking, it could use some sort of internal hopper or just take away from the unlocked inventory.
I suggest this because sometimes, especially in smp, there is a little benefit of using it on your doors and chests and even in mp sessions people can be friends and rarely need it. So it will somewhat encourage to either guard the warehouse, or lock your stuff.

And, as a small thing: since villagers can open locked doors, it will be neat addition to make it so doors in a village have locks. So in order to properly intrude into someone's house, you will need to either break a wall or a lock, or to walk with a villager. In some cases it can even be interesting if one for example has a mod which makes it so that touching village blocks will result golem aggro on you.