Yeah AW's CO roster is wildly imbalanced, but the core gameplay is brilliantly designed.
It's a game of subtleties. The game revolves around the 55% matchup - the standard damage for two units of the same type fighting each other (infantry, tank, etc). So it takes exactly two full strength hits to destroy a unit, usually...however, mitigating factors like the unit's HP being too low, terrain defense, etc etc cause it to take three hits to destroy the unit. Therefore, very small stat adjustments create a huge advantage! It's even got just the right amount of luck factored in, the fact that units can randomly do an extra point of damage introduces an element of risk without relying on swingy elements other strategy games have, like accuracy issues that make attacks miss entirely.
Add in the fact that units lose power as they lose HP and the damage you take from counterattacks, and that brings in the enormous attrition factor; you live and die by the amount of territory and funding you control, and create an environment where direct and indirect units rely on each other (to gain ground and hold it, respectively).
If it weren't for the bad CO balance, AW would be an almost perfect game!
since it is on a gameboy
The DS is the last bastion of gaming, you fool!