If you're happy to take orders and run with the other grunts, that's fine, but there are other exciting possibilities. Armed Assault enables you to flick between predetermined soldiers mid-mission - why not assault an enemy position as a regular trooper, then switch to a sniper to cover the next wave of allied attacks before zipping into the body of a tank-gunner to pursue the retreating enemy. And there are a number of vehicles to pilot, from tanks to missile-packing helicopters.
Between missions you'll have strategic choices to make about your next operation. Faced with having to either defend a city or invade an enemy camp, for example, you need to be aware of the consequences of your decision - if you destroy the camp, there will be fewer enemies to assault you in the city; but if you defend the city first, then you'll receive reinforcements while you attack the enemy camp.