I understand what you're saying, but it's not quite as simple as that. If they didn't want it to get compared to its predecessors, it shouldn't have carried the Final Fantasy name.
Now don't get me wrong, I don't hate FF XIII as much as most people do - X is my most hated Final Fantasy. But the fact is it does carry the FF name, and for a lot of people that means association with a lot of things. World maps, exploration, turn based battles, character progression, sweeping epic storyline etc. FF XIII got very little of those things right.
With sequels to games, I expect them to evolve from the original design. FF XIII (and to a lesser extent X) felt like redesigns rather than evolutions. They'd taken everything people loved and disregarded it to change the direction. It's a bold move to take with an established franchise, but not always the right move - especially if you're expecting positive fan reaction.







