No, the whole class isn't inviable. With the right setting you can beat the s**t out of everything
I'm a PE lover, my first class back in Neocron Beta was a PE, later in retail I got a PE, and on every other Server, too
The "you can do all, but nothing right" thing on that class, is what I like. But when they changed the requirements for the spells the PE was downgraded a lil bit, cause he couldn't use all the spells like before and now you loose focussing trough the MC5 Chips and most settings need 2 of them for the PE.