What if the potion preps were changed from 5 slots that you can fill with anything, to a purchase system where you can spend up to X kingdom gold at the Witch's hut and buy whatever potions you want. The hax potions would cost a lot more, and you would be allowed to buy duplicates - so a 40 gold cap would let you take, say, two health potions and two mana potions, but if you took a Quicksilver and Reflex potion then you couldn't afford anything else.
I mean, I personally view preparations as being the equivalent of a
trainer, i.e., cheat codes, there to put the game on easy mode if you're having trouble or you just want to mess around. But I'm not altogether sure what the devs actually think about them, since the church preps are completely counter to that idea. It is kind of bizarre that you're free to bring in all the top-tier potions and wreak havoc, but you're not allowed to simply prep GG or JJ or Dracul (for the sole purpose of not having to scum for them) without suffering crippling penalties.