What was unique about Mazer Rackman's teaching ?

Mazer knows a lot about the Buggers. He was kept alive at light speed just to teach Ender.This guy knows way too much about what to do. In the "simulation" Mazer will be programming the enemy and Ender will be commanding human soldiers AKA all his friends! Also Major has Ender try to connect with the Buggers on an emotional level to better understand them and then kill them.