Doctrinal, only last a fraction of the time the ability is active, just protects one vehicle, costs munitions, and you still can't use it in the fight. Unless you are suggesting getting a mortar to lay down a smoke barrage!
The argument that you "Block his LOS" just doesn't work.
If you pop smoke you just delay your tank getting gibbed by a few seconds. Try using mortar smoke barrage. It won't land till the ability is over.
The only thing I would understand is how the command vehicle gives free vision for no cost or risk and allows the ability to be used to it's full effect.
Your problem with it might not be it BUT the lack of usage of smoke.
And smoke is something I used alot with USF.
And also don't forget there are abilitys that might not disable units BUT don't even need LoS to fire and have alot of firepower.
I would suggest the command vehicle gets replaced with another ability in that commander,this way we solve the free LoS problem.