ff 3/6 thoughts

Well it's like complaining about healer because you have to waste turns to heal yourself: thief is a job like all the others, so i don't mind investing some turn in stealing attempts, what maybe i dislike is placing a crappy steal as common along with the rare one, since after you steal the common you'll lose the chance to steal the rare one... you should put common steal OR rare one, at least this is how i'd probably do for my hack

I don't think this is an accurate comparison.

Health is a combat mechanic.  Replenishing health contributes to your success against the opponent.

Steal, however, is a world mechanic.  It is a substitute for purchasing objects with gold, which makes it a form of character experience.  When you steal items, you're basically adding bonus shop experience to the fight.  If the items to be stolen CAN'T be acquired in another way, then it's a direct penalty for not bringing the thief to the party.  The Steal command is effectively incentivizing using a weak character with the threat of missing out on something good.  It's feeding on missable rewards, which I personally find distasteful.

There are FF games that did a better job with it.  For instance, Final Fantasy X had a very good steal mechanic: using steal gave you things to throw and mix (used by the same character) and also acted as a death spell against machine-enemies.  You also had the option to switch out your thief when you were done with her, save a few underwater sections where she was required.

While I can't hold it against FF6 for not having an idea before it was invented, I think Steal as a command is a fairly good candidate if a modder is looking to replace something.
Such as, say, throwing weapons being the things you steal and the person with the thieving daggers having the throw command.