The Worf Effect repeatedly inflicted on the teachers makes a lot of sense in light of the Headmaster's belief that the growth and interbreeding of the metahuman population is fast-tracking the world to an apocalyptic Goo Goo Godlike scenario. It's already happening. The youngest generation is already more powerful than the elder generation, just less experienced. As the kids become more practiced, the world is going to rapidly depart from anything recognizable as parallel Earth history and turn into an even more wild and terrifying Alternate Universe Reed Richards Is Awesome. - Nerrin
It also makes sense given that the times the Worf Effect has been the strongest in the comic is when the teachers were up against villains who knew who they were and therefore could counter their skills and abilities pretty easily (for example, when the powersuits fought Miss Kyle in the Las Vegas arc). The students, on the other hand, are almost all completely unknown and therefore are far less predictable- notice how they were only ever able to counter things that the Flea had already used against them.
Cecil's inability to detect Prospero as unusual makes sense - Prospero isn't superpowered, he's a perfectly normal... whatever he is.