I admit calling DoB a direct sequel is wrong it is a distant sequel to the original FFVII, It seems that we are not on the same page when talking about sequels/prequels. I am saying that in a narrative/story stand point it doesn't matter if Zack is the main character in CC due to the fact that the main story of CC (In a narrative sequence) will lead you to the events of FF VII and that is why it is a direct prequel from the original game. As i explain further why CC is what you also called a spin off because it was part of the huge (Zack is the main character which obviously who plays a minor role from the original game and thus the whole CC revolves much around him same thing can be said on FFX-2 which evolves around Yuna technically X-2 is also a spin-off of the original X game) next is CC is part of the huge story of FFVII as a whole (CC, DoB, Before Crisis, Final Fantasy Last Order & FF 7 AC) but each of these were all a sequel from the original FF VII in a narrative/story standpoint.
Yeah i can see that!!But what is the exact thing on why people are displeased on the game? And there can only be something within the game and it revolves around this categories (Story, Plot, Gameplay Mechanics, Battle System, Characters, World Building). Call of Duty is hardcore gaming and literally majority of the Hardcore gamers would like that.
Yuna was not a side character, she was the main character along with Tidus though. But fair enough, we'll call CC a direct prequel. It doesn't really change my point, there's still never been a direct sequel/prequel that has done as badly as LR did, since CC got about 30% of the sales VII did.
I find that people dislike the game for many different reasons, some dislike the story, some the gameplay, some the battle/level system etc. Whatever those reasons are in particular don't really matter as on the whole a majority of fans were unhappy with the game. That, to me, is not a success when the game is in a series and the next games in the series could suffer (or have suffered) because of it.