Since I haven't read beyond the second book in the series, it's impossible for me to say if this film is too meandering and maudlin due to the original story or the screenplay or the directing. My guess is all three.
The first 30 minutes or so actually worked fairly effectively. There is a sense of loss and danger. There is a thrilling escape. There is a growing threat. Then we spend two hours wandering from place to place with no clue as to why we are anywhere. It's just a series of set pieces that eventually start adding up to something. Then we finally and surprisingly find the one person who can fit all of the pieces together and we get an information dump about what is going on (at least it's a somewhat interesting and entertaining dump).
High marks still for special effects and world building (although the number of people working at the Ministry of Magic seems implausible to me). Decent marks for acting, based on what they had to work with (the romances here seem to have been written by George Lucas). Low marks for storytelling and pacing. I'm glad this will all be over soon.