This would effectively remove the unit from the game because the unit itself is only good for it's aura.
It should just not work in enemy territory. That's all. Also remember only one of the doctrines it comes with has a heavy tank, most of the rest of them rely on medium and light armor, the buff to it has made the game much more fun because more Ostheer commanders are meta!
I'm not saying remove the aura, I'm saying that IF the aura is too strong in enemy territory then the best way to approach the solution would be to reduce the strength of the aura a bit instead of adding a bunch of complicated rules as to when it works and when it doesn't. Keep in mind that nothing has changed about the command tank's main gun so it is still quite decent vs infantry and light vehicles. If the aura was a bit weaker then the main gun could also be a little better or the price of the command P4 could be somewhat cheaper.