Well, Gene's dead. The franchise passed on to Rick Berman, and now it's J.J. Abram's universe to mold how he wants it. Just because Gene came up with ideas doesn't automatically make them good ideas:
The idea of no money in the 24th century? Yeah, bad idea, as we saw later series' struggle to shuffle that little issue under the rug or hand wave it away.
Gene wasn't this savant, and he wasn't some immortal visionary. Gene had serious faults, even when envisioning his own production. So "Gene thought it should" means exactly dick, especially some 22 years after his death when incarnations of Trek have changed so drastically.
Michael Piller said:
You think Deep Space Nine would have been the series it was if Gene was still around? I doubt that very much.
As cool as Gene was, and for all the good he did, sometimes he had absolutely terrible ideas. DS9 was a terrific series, and it would have happened even if Gene didn't want it to, much as TNG was already changing it's formula even though Gene didn't want it to.
I'm not saying the writers should have known that Fermat's theorem would have been solved, I'm just saying that they should have used something that was a bit more relevant to the story at hand. I would have been happy if Picard mentioned how there was an alien species that copied details from an Earth Book and built their entire civilization around it just like in this episode. Picard would than discuss how despite humans and aliens having spent years trying to understand one another, you can't just base your findings on one source alone, like the aliens did with that novel. Picard could have contemplated that if they had just brought a different book, or a whole variety of books that better reflected humanity as a whole, we probably would be friends with the aliens already. That would have been a more interesting discussion than simply brushing everything under the rug and ending with "Like Fermat's theorem, it's a puzzle we may never solve."
No, that's a good kind of closing, because it left things open for future exploration. Nothing came of the mystery that is the unknown alien species that created the Royale, but that doesn't matter. It was a nice 'question mark' type of ending, something right out of a pulp novel.
The Royale is one of my favorite episodes. It is distinctly Second Season, late 1980s television, and I love it.