Actually, if your hypothetical four-place word is the nearest equivalent, wouldn't it be technically true to say that one can't, or at least can't simply, describe something as having-the-innate-quality-of-goodness in Lo* at all? That's how I understood it to work, and it was one of the things I liked about the language when I was studying it.

In effect, yes. The four argument-places of "gudbi" are always there. You never have to fill in any of them, but leaving a place syntactically empty means not that there is nothing there semantically, but that it is filled by whatever you intend fills it. By omitting to say what, you are assuming that it will be clear to your listener from context. Most adjectives -- that is, predicates that correspond to English adjectives -- are comparative in Lojban. They mean "X1 is more (whatever) than X2 (perhaps with additional places)".

Of course, people who have the idea that goodness can be an innate quality will try to use it that way anyway, regardless of correctness. How does the Lojban community handle that kind of thing?

It's been a while, so you'd have to ask the Lojbanists themselves about that. If you wanted to say this explicitly, you'd end up with some circumlocution that would back-translate as something like "this is-an-example-of the-mass-of-good-things", and even then, the listener can still come back with "gudbi ie", or "better than what?", just as readily as the English sentence "I gave" immediately suggests the questions "what? and to whom?"