Do most people just randomly pick. I have only played a few times. Today I played solo with Prince, Seer, Priest and Scholar. There just wasn't anyone really good at fighting and I just got overrrun
After a few games (or after you read all the power cards), you will get a very good idea of what each hero's role is. Then you should be able to build your team very efficiently, with 1-2 fighter heroes, 1 search support hero, and 1-2 general support heroes, and you will immediately notice how smoothly things work.