I can't say I'm surprised it hasn't sold as well as its predecessor. I didn't like FF XIII one bit, but to me it was just another bad game. Many people pointed to it as an example of the Japanese gaming industry's stagnation or refusal to adapt, some saw it as an example of the gaming industry's insistence on placing spectacle and cinematics over interactivity. Perhaps it was both of those things and more, but to me, it was always just a bad game, a poorly designed game, but nothing worth dragging through the mud the way some people have.
But what I do hate, what I really abhor, is FF XIII-2. I don't even need to play it to hate it, because of what it stands for - Square Enix's tremendous arrogance.
They decided, before FF XIII was even released, that it was going to be a franchise. Not even just that it was going to have a sequel, it was going to be a franchise. Before any fans had seen it, before they knew whether anyone liked it or not, they'd decided it was going to be a franchise. Before FF XIII was even released, they were working on its sequel and co-titles. Even after it was released, divisive even among ardent fans, maligned by others.
But no, it was still going to have a sequel, to be a franchise. Because they know what's best for us.
It's just disgusting, frankly. They threw the Final Fantasy VII franchise at us, but as widely disliked as that game is now, it was once considered one of the best. It had an enormous and devoted following, and had a huge impact on gaming. So a franchise at least made sense - they were giving a very large number of people what they wanted.
But in this case, SE were deciding what we wanted before hearing anything about it. And then when they did hear about it, they ignored their fans, and carried on anyway - only a token promise of "more freedom this time" to indicate that they listened at all.