That's mediocre? Come off it.
I've never ever played a FF game in my life. I am interested in this, what do I need to know? Is it just hack and slash and is the story different to other ff versions?
They're stand-alone, not hack and slash, and are great at delivering high production, epic fantasy. They're not perfect (apart from FF6, which just is!), but if you want to get caught up in a ridiculously epic story with over the top, outlandish characters and loads of stuff to do, no other series does it better.
I would go as far as saying both 7 and 10 were pretty perfect Final Fantasy Games.
13 I found absolutely abhorrent
The reviews alone put me off. Sounded like a long corridor punctuated with random battles. XV looks leagues better