Some of the things in the plot just don't make much sense. Why did Voldemort wait until Harry won the Triwizard Tournament to capture him? Why not just use something else as a portkey (Moody/Crouch Jr. could hand Harry a piece of parchment or something)? And why didn't Harry just summon the golden egg to him, rather then summoning his Firebolt to fly past the dragon? I was also pretty annoyed by all the last-minute revelations, the pages and pages of monologue from both Crouch Jr. and Lord Voldemort that were used to explain all the important plot points in the book.
On the other hand, reading this was so much fun! I liked that we got to see so much more of the Wizarding World in this book, the different schools, and international wizards. Some of it was unnecessary, and I felt like important parts of the plot were crammed hastily into the last few chapters, but the journey from beginning to end was so enjoyable I can (almost) overlook the flaws this time.