Ok, here is what you do. You use the MM to create a "balanced" creature encounter. Include a controller, tank, striker, leader, whatever. Then you show them how the roles should be used.
Example
Use the controller to take the 2 melee strikers out of combat. Then send you speedy lurkers and skirmishers against their ranged strikers. Lock down anyone else with a soldier or brute and TPK them. Then tell them to make a party that isn't complete non-sense.
Lesson, having an all striker party makes your job a f'ing nightmare. You will have to be completely anal about making your encounters so they don't die. Well just kill most of them, and let them make a real party. Plus it would be fun to show them how awesome a balanced party truely can be.
Example
Use the controller to take the 2 melee strikers out of combat. Then send you speedy lurkers and skirmishers against their ranged strikers. Lock down anyone else with a soldier or brute and TPK them. Then tell them to make a party that isn't complete non-sense.
Lesson, having an all striker party makes your job a f'ing nightmare. You will have to be completely anal about making your encounters so they don't die. Well just kill most of them, and let them make a real party. Plus it would be fun to show them how awesome a balanced party truely can be.