Compare the Command PZIV and normal PZIV vs any meduim tank and you will see what you have sacrificed. In addition the CP for command tanks is allot later.
Calculated the DPS a vicker, a sniper or 2 Ro Eng with dual piats and you will see what you gain from a command vehicle from CP2.
The command PZ4 sacrifices its anti-tank capabilities to still have really good anti infantry capabilities. So it's basically like an ostwind.
The aura is pretty good if you use it on your whole army, but that goes without saying just like any aura in the game. Thing is, the tank itself is worthless and having to go AEC contradicts the commander which are both glaring problems. I can see your complaint that it comes in at 2 CP though, and that's probably where the problem lies.
It has to make the tank crappy because it comes so early and the aura makes british infantry strong, but if the command ability came later it wouldn't have to nerf the crap out of the tank and would probably make the ability feel good to use.