We tried many times other compositions, each time we failed hard because we lacked medics or ran out of ammo and had to play with suicides. Four soldiers could be killed only by an engi and a medic, you don’t get more offense only with soldiers, or with more medics. The basic array has at least 2 medics and a field op, otherwise you get pawned with the current class model and balancing.
Have you tried comp playing Djiesse ? Because 5vs5 is really different from 8vs8. So IMHO, until the classes are fully defined with all their guns and skills, it’s pointless to try to balance them. Otherwise each time a new feature is released, SD will have to rebalance elements of the game, which will make them lose time instead of actual development.
Finally, 2 medics + 1 field op leaves 2 slots for strategic gameplay. But you may strategize as much as you want, without 2 medics and a field op, you lose for sure in the current game’s state.