Come on, even fans of the series will admit there's only a few good ones, and none of them are recent releases. If it wasn't for the past few, it could have ended as a good series for the people who like the genre, but what it's become now is kinda sad.
What does the "of" in "could have" mean?
Also, you seem to be missing the point about Final Fantasy, it isn't really a "series", each numbered entry one offers something different and new, which is the point.