In terms of gameplay, the series is getting better. Sure there are still a few "press X to win" moments here and there, but with the introduction of flowmotion, deck commands etc. the series has given you more ways to fight. So I'm excited for what the development team will think of next.
Now with the story, I had no problems with it until DDD. The introduction of time travel threw me for a loop and I still don't completely understand it yet, but we'll see where that goes.
Personally, I would like the Xehanort saga to end so the series can make a fresh start. A reboot of sorts if you will. Have Sora and co. finding a way to return the true light to the world, or something along those lines.