I really like salve maker and how it's competent beyond ffvs 'mix is OP, but I hope you have a spreadsheet handy'(Potion + phoenix down is pretty sweet though).
Chemist and Chemist-like jobs have, with exception to FFT (debatable since Auto-Potion is a fairly useful reaction ability for a good while through the game) and the TA games, been gamebreaking to some degree.
In FFV, Chemist abuse can lead to things like one-shotting the final boss.
In FFX, Riku starts with it (but its probably at its least broken given how most of the useful combinations require items that needed elsewhere).
In FFX-2, pair an Alchemist up with two Dark Knights and you're set for life.
In 4HoL, Salve-maker made your items free, let alone boosting their effectiveness, allowing you to multi-target, and reverse their effects. Don't know what Alchemist does in this game since I never got that far.
That said, one neat thing is that when you're running through your options, is that you can see the name of what you're going to mix before you mix it thus making trial-and-error less annoying than it would otherwise be. Also the game provides a D's Journal sub-sub-section dedicated to listing every used mix result and a list of all possible item combinations needed to achieve it.