Hello! I am collecting axis and allies because I love them and have different gameplay, but I am falling in love with SSU just for their walkers, helis and tanks, but i don't know if you can build a good army without using so many infantry units (just command squad, some heroes and some red guards), what do you think?

One big problem with that approach would be buildings.

Since armored units and planes/helicopters can't enter structures, you need infantry units to go in and clear out the enemy infantry.