Oh believe me, RNG is FAR better than it used to be. I say this a lot, but RPGMaker RNG is crazy. You can tell it to pick 1-3, and it'll give you five 1s in a row sometimes. I've had to get used to coding around it. And yeah, stun can be annoying, but it's needed, because without it it's far too easy to steamroll the enemies in the early/mid game. I also have a back-off built in on that so in theory once you've hit 3 battles with stun your third should be guaranteed stun-free.
But I would say in general, if you're managing your items carefully, healing with your skill outside combat etc, you should only have have to save-scum maybe two or three times in a typical playthrough (and sometimes never). And while not wasting items is important, I wouldn't worry TOO much about saving them once you hit the end of mid-game (right around the end of Entertainment District I). There should be plenty for what you need to do.