The folks at SE shouldn't just put any random stuff in a sequel; they have to make it with quality plot elements that continue the storyline of the previous games.
Which... I can't ever remember them doing... OH! Unless you count Tactics Advance! That was a good game. And so was Tactics A2! So they just need to make a Final Fantasy IV Adva- oh, wait, never mind.
Can we get a FFV DS remake already? =D Or even a prequel to V about the Dawn Warriors? =D
Or perhaps a Final Fantasy III prequel about the Dark Warriors.
Why is it that half the games have more interesting backstories than actual plot events?
It's better than having no backstory at all, if you ask me. The first Final Fantasy had no backstories for the main characters. The original FFIII had no backstories either, but the DS remake gives them backstories and names.