I don't even think some of the stat potions have a worthwhile impact. I can craft them and gather and hunt down all the material. I enjoy doing that so it doesn't feel like time wasted and I save gil.
But if some or most of the stat potions with there 15 second duration have no noticeable impact then why should I bother to craft them to use myself, let alone expect anyone to want to buy them.
I would like some evidence that a mega-potion of strength or a mega-potion of vitality that last 15 seconds has any significant impact at all. I've been experimenting with the mega-potion of strength while running as Paladin. I often pop one then do circle of scorn, spirits within or a rage of halone combo. I can't see a significant effect to use it as far as I can tell, even if the hq versions give an even bigger boost to the stat.
I feel like some of the Alchemist potions are just filler for the Alchemist crafting list.
I understand Square not wanting to serious imbalance the game. But if you give us something to craft like this, it should it least be of some use please.