I am a huge Final Fantasy fan. However, I wasn't a huge fan of XIII. Usually they are amazing at developing that player to character relationship. In XIII I really didn't care what happened to them, unlike other FF games. I actually found most of the dialogue between characters incredibly annoying and it was full of vague conversations that didn't go anywhere. So many times throughout the game I found myself yelling "Just tell them what's on your mind, instead of beating around the bush!". Then they would continue to whine because they didn't tell them how they felt! It felt like they didn't even try with the dialogue. Sometimes seeing a character build resentment towards another character without confronting them works, in this case (specifically Hope's problem with Snow, no spoilers). I found that whole situation incredibly annoying and drawn out.
I am also very unimpressed with the names they chose for their characters. A couple of them weren't bad but Hope? Snow? Fang? Lame.
I also didn't like how linear the story was. I was hoping to be able to travel where I wanted to go. Similar to FFX where you were able to travel to different locations on the map when you wanted to, once you unlocked the airship.
A lot of the information I have read is saying FFXV is going to be great, but we will see. In the previews i have seen all the characters look the same, so I will wait and see if these characters are going to be forgettable or memorable.