Uhm, Geschutzwagen is Wehrmacht, Marder is PE. That's the difference (you can tell because of the skin)
Geschutzwagen is likely to replace the StuG. Possibly the Pak38, but I doubt it for balance reasons. No official word. The Hotchkiss, what it will replace for the PE, I have no idea.
BTW: Axis Howitzer (probably not multiplayer, screen is from causeway campaign)