agreed ,ending was a bit lame , i mean the idea itself (spoiler alert!) that harry was horcrux was cool , but last sceen , as well as the way he met dumbledore was blah
in the oher hand in my series of movies , i'd push the actors into performing better , lie in the fifth movie when H.P used cruciatus on pilatrix , DUDE she just murdured your only family ,show more enthuthiasm at least ,plus i'd add ntensly anger/danger music and let the curse last for more tha 0.5 second
and basically show more of reasons and stories behind everything , plus more of the substracted characters , emphasis on things such as school stuff and the little things through out their life that are similar to the childhood memories and current life of most people , so that people connect more with the movie , use of more interesing camera angles (such as bird eye , or focus on the further character while showing a single tear on the cheeck of he closer,blurry,neglected character) , maing nevel longbottom develope into a talented wizard after emphasising on his story of gettig over his parents tragedy instead of just an overly emotional person (even after he made the little revolution) . anyway , a lot of little modifications to the story , and the style of direction , i'd have made sure that the movie stimulates empathy and raging tears with he help of right implementation of music ,sequence of events , acting itself and camera angles
and of course , the ending would be more epic , maybe even let harry sacrfice himself to kill voldemort and then his spirit stays in the school to tell the story to all coming generations so it won't be a very sad ending , and then give the ending that says that the story will go on by another prophecey by another wizard , maybe this time it would be a girl H.P