There is nothing that can replace it. Not within the scope of your argument (that the unit should synergise with other the other Elite Armor abilities).
I did not suggest that a another unit should go to elite armor to replace ST.
What I am saying is simply 2 abilities of the commander do not work with ST and that makes ST less attractive with in the Commander. One of the also allows tank to call in arty making the ST shots even less attractive.
One can replace the ST in Elite armor with a ability that makes vehicle cap territories or a cheap repair unit that uses crew uniforms so that SP can have help.
And it can't be rebalanced within realistic terms either. It has gotten a lot of QoL buffs lately and it's good enough for casual play now. There's not much more that can be done within Relic's current scope of no major changes. Similar to a unit like the B4, it will just never be competitive due to its nature.
As long as Relic's "scope" is not public there will suggestions outside the "scope". It is my understanding thou (and i can be wrong) that Relic has allowed many thing that there were originally outside of the scope.