Overall, both of these vehicles are essentially the Sturmpanzer 2, only with a worse chassis. The Sturmpanzer 1 is literally a German 105mm howitzer, which was rolled onto the chassis of a Panzer 1 tank. In combat conditions, it could be rolled out and used as a regular howitzer. It used during the Invasion of France and on the Eastern Front in the early stages.
The G.Pz. Mk. VI is the same howitzer on the chassis of British Mk6 tanks abandoned at Dunkirk. Twelve of these vehicles were built, primarily serving near Leningrad, where six were lost. The rest were lost in unknown areas of the Eastern Front. Some vehicles may have remained in France until the end of the war. Nothing is known about their combat use.
Personally, I find the G.Pz. Mk. VI a much more interesting vehicle. However, it has less chance of being implemented than the Bison, as the game already has the necessary chassis for the Bison, which is also the basis for the Flakpanzer I.
KV-2 is borderline, but M4A3 (105) should have been kept at BR4 for sure.
However Chi-Ha naval is definitely not BR4 material and StuH42 or Semovente 105/25 M43 are certainly not better enough to be a BR higher.
There are things we need to consider when we talk about that which vehicle should be added. The most important thing needed to be consider i think is that if such vehicle already exists in Warthunder. Enlisted basically been importing almost every vehicles from Warthunder and i doubt that Darkflow would make completely new vehicles just for Enlisted at this point. So i think both G.Pz. Mk. VI and Bison being added in Enlisted would be very very very unlikely if i were to guess.
However, StuH 42 with 105mm is very likely. Already exists in Warthunder and in the editor as well. Plus, 105mm gun with a good armor on BR 3 as TT vehicle would be a fine competitor to 105mm Sherman on BR 3.
