Well, cloning cuts costs so we get more rides. If not for the availability of clones, we’d have no Mine Train or Rat. They were literally chosen as they could be easily cloned to keep budget under control.
Indeed, there are conflicting desires among the fan base:
People say Disney is too expensive and then want Disney to build one-of-a-kind top-tier attractions for each park. That's going to drive up cost, and then ticket prices.
People say DL and MK are too crowded and so Disney should build another Disneyland elsewhere (Texas, Australia, Brazil). But that only works to alleviate crowds at MK and DL if the new Disneylands are clones. If DL and MK have unique attractions not cloned elsewhere, well, then, the whole world will have to come to DL and MK to experience their unique attractions, and not just those who are in the global region.
Not to mention that good ol' Walt was the original clonemaster building MK as a clone of DL. Epcot was unique only because the corporation decided to do something unique with a theme park after Walt died. Walt's EPCOT was not a theme park.
I'm of the opinion that if you want a unique attraction, then put it in a unique park, like Tokyo did for DisneySea, or for what WDW did for Epcot and DAK. People should travel the world for a unique theme park, not for just one or two unique attractions.
Of course, this is a moot point right now as the billions of dollars being dumped into the international parks is to add whole new thematic lands which are going to be cloned elsewhere.
The bright spot for those who want one-of-a-kind attractions is that the Marvel Lands will have unique attractions. Tho, I'd bet money that in their phase 2s, they'll just start cloning the best attractions of one another.