Better View is not necessarily the Easiest View.
First, as you probably know, the audio/music portion of the fireworks is piped into both Narcoossee's & CA Grill. You cannot go wrong with either. And unless your meal is entirely about eating a Maine Lobster, CA Grill has, in my opinion, the better food.
Then assuming you're not planning to be at Disney during time CA Grill is being refurbished - it is easier to see fireworks from just about any seat in CA Grill than from Narcoossee's. There is also an outdoor area at CA Grill where you may stand to view the fireworks. And the resort-wide view from CA Grill is lovely and you might also see lights/fireworks from other Parks too.
However, Narcoossee's may have the better view of the MK fireworks, since you are more centered to the way the rockets are sent into the sky. And while the view from your seat inside Narcoossee's may be a bit obstructed, you are also welcome to view the fireworks from an outside balcony.
My family just spent a week with a MKingdom view from Bay Lake Tower. We could see fireworks from our room, from rooftop lounge at Bay Lake Tower, at CA Grill, and Narcoossee's. In my opinion, the best view was from Narcoossee's.....but the entire ambiance at CA Grill is a bit more spectacular.