"People will only pick the optimal" is completely untrue. If that was so, why do games like Diablo even exist? People like choice. Just because a few elitist blowhards will try to force people into builds doesn't mean everyone will... Just look at extreme primals, and other end game content, you see DPS classes being out damaged by tanks, and they barely ever get called out about it. You wouldn't even have to worry about an optimal build outside of a raid group.