There's a real baby-with-the-bathwater challenge here. I can see the issues with over-the-top schoolwide assemblies at botht he beginning and end of every fund drive. But I also know that both types of assemblies result in higher fundraiser earnings, which often go to saving or providing essential school services. I would think the prizes, especially (as opposed to the kick-off), could still be played up big even without the assembly.
What's going on with your group when it comes to kick-off and reward assemblies?