Most of the arguments for 102 extra planets in our solar system seem to be based on the public being excited about having a planet. I don't think it'd work that way. Having 110 planets would water the concept down. The problem is that an object is perceived as less interesting because of it, and that's not true at all.
There's nothing to stop a moon from being as large and complex as any planet. Ceres is categorized as a dwarf planet, and it's got surprising geology, even a chance of harboring water and life. The surface of comet 67P has proven to be amazingly interesting. Pluto didn't need planetary status to knock our socks off in 2015. We *are* going to find more rogue planets floating through space with no parent star that we can see. We are likely to find Planet 9 soon, and there's a chance it's not a planet which Jupiter and Saturn kicked out during our system's formation, but a captured exoplanet. These are all fascinating objects!
It's a question, though, of where they form, how they exist, what bodies they're interacting with. It makes no real sense to me for Europa and Ganymede to not be moons. Their primary gravitational attraction is to the planet they've formed around. That planet is something formed together with its parent star from the same disk, because of the gravitational eddies and changes that produced that star. They're all made from that system. That's what seems to be behind all the particular stipulations of what a planet is.
I'm okay with that!