Unfortunately I can't tell you anything about the Black Guard, because it was never put into beta testers' hands. I do know that it's the mirror to the Dwarven Iron Breaker career and had a mechanic that was very much similar to grudges. However, for the Black Guard it was called "Hate" instead. There are some NPCs in the game that appear to be wearing what looks like could be high level Black Guard armor. They look really, really cool. I'm not sure if that's a form of comfort or just pouring salt on old wounds. Hopefully we'll see the return of the lost careers.

As for the Choppa, Hammerer and Knight of the Blazing Sun, they haven't been in the beta for quite some time now. Back when it was available, I mostly played the Choppa (green is da best!) and can tell you it was a career with a lot of promise. The last time I played it was late last year, just before the original beta shutdown that lasted a couple of months. Its mechanic was all about building up a huge WAAAGH! rage and going crazy for several seconds. During that time, the Choppa would glow red and unleash some particularly nasty abilities. It was a lot of fun to play, but probably would've needed some serious balancing tweaks. I do hope we see the the career make an appearance in the game sooner rather than later.