A very controversial spell

[olentu]

It does, however change their alignment, which has an effect on personality.

You're right though, their natural inclinations wouldn't change, but their moral frame of reference does which can bring conflict to a character (which is why they're not necessarily going to stay good).

And yet, by your own measure that does not happen. If the mechanic doesn't say it does something, it doesn't. And so the spell can not change the personality. Well unless, of course, your are claiming that the alignment can affect a character's actions by imposing some sort restrictive moral frame of reference. Almost as if there was some sort of bindings, perhaps made of cloth, restricting their actions.

Well that, or perhaps you wish to relax your standard and allow for consideration of what the spell implies. I would certainly not find it unreasonable for one to interpret the spell as heavily implying that there is a personality change, but that does not matter so long as implications are right out.

Or rather, it doesn't change their personality more than it says it does.

If the Evil Villain collected Wingback Chairs, then after the change he'll still collect them. If he loved to cook, he'll still love to cook. If he liked sarcastically mocking people, then he probably still does that. Etc, etc.

It's arguable that if he loved to fry orphans, then he doesn't like that anymore. Some changes are to be expected.

Now now, changes are only to be expected if we are allowing for the things the spell implies to have any weight. However spells don't imply anything. They tell you what they do. If the mechanic doesn't say it does something, it doesn't. And thus nothing that is not explicitly stated in the mechanic can be expected.