I wouldn't say "kiddy", but it sure seems to focus a lot on trying to be "cool".

It started out with Cloud, a cold dude with a huge sword and a punk-haircut, and then there was Squall, the "bad-ass".
This temporarily stopped in FFIX, where characters felt more likeable and overall nicer.
Then we got Tidus, and he also felt kind of exagerrated; he was more the kind of character that 10-year-old boys find "cool".

Cecil and Kain in FF4 were a bit like this as well, but there just was something about them that even I liked.
They felt more "alive", somehow, like characters that were created with a passion.
Nowadays FF characters feel so commercial; it'll be long before we see characters like Rydia, Terra, Locke and Garnet again.