Ok, let's say I LOVE "A Bug's Life", and I think it deserves a sequel. So let me give my opinion on what happens.
After the untimely death of the Queen, Atta takes the throne. She likes Flik a lot more now, but before she can make him her king, the despicable Queen Honeycomb threatens to overthrow Ant Island and make her new hive and kingdom there. Flik has no choice but to track down the Circus Bugs, and with a new friend from the circus troupe (Molt the grasshopper), Flik and the crew plan to overthrow Queen Honeycomb, her faithful allies Bizz and Buzz, and her Bee Drones themselves.
The cast will be...
Dave Foley - Flik
Julia Louis-Dreyfus - Queen Atta
Hayden Panettiere - Princess Dot
Jennifer Saunders - Queen Honeycomb
Andrew Stanton - Bizz
Lee Unkrich - Buzz
John Ratzenberger - P. T. Flea
Denis Leary - Francis
Jerome Ranft - Heimlich
David Hyde Pierce - Slim
Bonnie Hunt - Rosie
Tina Fey - Gypsy
Bob Peterson - Manny
Brad Garrett - Dim
Michael McShane (or Kenn Navarro)- Tuck and Roll
Richard Kind - Molt
Jess Harnell - Mr. Soil
Rodger Bumpass - Thorny
David Ossman - Cornelius
Edie McClurg - Dr. Flora
If you want this to be different, let me know by commenting, and I'll see if I like your ideas!