Well, from what I gathered, the save doesn't make a huge difference, really. Playing an alchemist is more challenging than a swordsman, but in a weird way. In certain fights, especially in Act II where you don't get to use potions, there's a lot of "oh shit" moments that are a cakewalk as a swordsman. On the other hand, the rest of the time it makes the game much easier. I guess if one had prior knowledge of what's to come, it'd be possible to find some sort of happy balance.