This is how I feel about it too. It wasn't the worst movie I've ever seen - it just didn't feel 'Final Fantasy'. Ironically that's the same criticism I have for FFXIII...
As for Kingsglaive, though, I'm not worried. Since it'll be running alongside the events of the game itself so it won't feel like it's just coming out of nowhere. I just hope it's going to be fairly dark, mature and 'gritty' in regards to having a decent amount of intrigue and the like. It certainly seems that way at least.