It's quite inconsistent now that the most natural type of armoured battle machines (those with mixed weapon, smth like main battle tanks and assault armoured machines), just as the most natural types of battle orders (mixed ones too - infantry with battle machines and mixed weapon types) are rather meaningless against most of decent, nearly-equal-tech enemies, at least during assault or meeting engagement, because with current ground battle model they have no option to select their targets, and so relatively low fire performance of armored battle machines makes them nearly useless in the beginning of battle with it's huge numbers of small targets. Battle machines with this ground battle model have only a niche of baffle pursuit force: elements, that are designed for the finishing blow against enemy's survived armored machines in the end of long, multistage battle.
To give them an ability to contribute in battle from it's beginning and to open a niche of midsized assault machines, I'd suggest to change battle model in two ways:
1. More dividing of front line and battle phase, so that each battle location will be separated from direct fire of units, placed on other locations, and, on the other hand, each battle phase divided to more successive (iterative) subphases.
2. Confined breakthrough rule can be added to these subphases, adding assaulting units an ability to continue an advance, while their opponents are suppressed. Confined breakthrough might be different from full breakthrough in that during subphases there is no ability to change opposing formation or even location, so assaulting subformation is just continue to push with their high-morale units againt opponent in the same location. That will make those units with high armour levels effectively more fire performance and give armors their natural assault role, instead of finishing blow tool in the most intense battles they are now.