Firstly, if you don't like the roleplays that are out there, make your own. Plain and simple.
Secondly, I'd hardly say fandom-roleplays show "no originality". I can't speak for all fandom roleplays, sure, but many of them go above and beyond simply taking a pre-made concept and doing nothing to it. Many create their own plots given the world they're working with, their own antagonists, and so much more. For example, a friend and I have a nearly-finished Pokemon RP that's been months in the making. And by that, I don't mean it's been running for months, I mean we've spent months making it, just to have enough for an OOC. We created our own region, our own evil teams, our own plot, our own gym leaders, decided what Pokemon you find where - or rather, actually, we still need to finalize that bit, but you get the gist. A lot of work went into it, and I'm sure much more will once it actually starts and we sit down to fine-tune the plot that our players will journey through. I'd hardly call all fandom roleplays unoriginal, especially when most non-fandom roleplays are still guilty of rather unoriginal and recycled ideas like high school, wolf pack, medieval fantasy and zombie apocalypse RP's.
Thirdly, there's a good reason why fandom RP's thrive, and the reason is this; the more original something is, the harder it is to understand. Fandom RP's use a pre-existing world and concept, and advertise to players who already know and understand these worlds/concepts, and that makes making, and joining RP's easier on the GM's/players than more original concepts. Say, for example, a GM creates a world containing 700+ different species of monsters that the players will expect to encounter in the form of NPC's. That's a LOT of information to take in, and a lot for the GM to manage. Odds are, almost no one will join, and the GM either has no life or will destroy theirs spending all their time to manage that RP and keep all the information straight. Meanwhile, a GM starting a Pokemon RP will be wildly more successful - because both the GM and the players are already all quite familiar with their 700+ monsters. Same goes for an original game based on a video game made to destroy the universe while simultaneously creating a new one all while dealing with an extremely complex in-game plot along with time-travel shenanigans, aliens, and a mess of player stats to keep straight - as opposed to joining a Homestuck RP, where all this knowledge would be common amongst players and easily understood. Hell, this is the same logic that keeps common RP setups such as high schools and zombie apocalypses widespread - they're something we're familiar with and easy to understand, thus it's easier for GM's to run, easier for players to join in on, and the whole thing requires so much less effort to get started. The more original the idea, unfortunately, the more you're asking for from your player base, and that's not always something you'll get, especially if your RP seems to contain too much new information for players to digest.
