Don't compare them to older games in the series.
I recently picked up XIII-2 and found myself utterly disappointed (as I expected after X, X-2, XII, and XIII - you would think I would learn by now). By this point, I was so desperate for a final fantasy fix that I decided to go back and play FF 9, which reminded me that FF 9 wasn't as well received as it's predecessors.
Then I remembered that FF 9 was my first final fantasy, after which I went back and played all of the earlier ones in order. This meant that most of the criticisms that plagued 9 were irrelevant to me. I didn't mind it going back to the old school formula since I had never known the new formula. I didn't find the battles slow paced or the story less epic. I didn't mind it's lighthearted approach and fantasy setting because I hadn't yet experienced the more serious and realistic tone of 6, 7 and 8.
This made me realize that all of my complaints about XIII and XIII-2 would have never existed if I had never played any of the previous titles. I wouldn't have minded the removal of turn-based battles, or that they removed most of the traditional spells and summons. I wouldn't have minded the absence of sidequests and overally linearity.
Thinking back, XIII and XIII-2 are likely good games in their own respect. They are certainly not without their flaws, nor are any of the other final fantasies that I remember with fondness. Square is still a talented company (though one with poor management and customer appreciation). Honestly, I think the best thing Square could have done for the game was to simply title it by a different name so it would be judged on its own merits.
So thoughts? Would your opinion change on XIII if it wasn't a part of the final fantasy series? Would you have enjoyed it more?
How do you breathe again?