Spot on. Well, except the part about finds documented on EDSM: it's finds documented by the GMP instead. It's a separate project, one that's hosted and made possible by EDSM.It’s actually five water worlds in a string of six planets, in one system. I’ve seen much less interesting finds documented on EDSM. But if that doesn’t float your boat, safe travels.
Also, contrary to popular assumptions, there are no clear set rules, there are guidelines, with exceptions made.
I rather liked @LCU No Fool Like One 's earlier thought: "Rarity is less important to me than gorgeous views." Personally, I think that the GMP should focus on visually interesting / spectacular stuff instead. For other uses, it's often obsolete anyway, and curating a list of systems with impressive sights isn't something that could be done well automatically.