How come the Borg come to Earth and fight through 24th century Starfleet defenses before going back in time, instead of going back in time first and then going to Earth with nobody but 21st century defenses in their way?
And why pick a date back in time with such a short window of opportunity for success ? And why didn't they just go back in time, tell past Borg about the federation and let that be the end of it ? And why not send 15 cubes to Earth ? And how did Geordi re-create the temporal anomaly ? Can Starfleet go back and forth into time at will ? Why didn't they just slingshot around the sun ?
This movie makes my head hurt. At least it's entertaining.