When we started playing DnD in the late 70th, it wasn´t perfect at all. Layed out as a pure tactic game they had to develop it further to the wishes and imaginations of the gamers. So give them time to adapt. And btw - a group of four is enough ? - that may work, but again it´s getting more tactical. Our groups were mostly of six: fighters, wizard, cleric, thieve/rogue, ranger. And you could stay in your role and play an rpg and not a tactic surviving game. A group of four forces the player to think already tactical when just choosing race and profession. It forces them to construct an egg-laying-wool-and-milk-pig. Like Mercer did in Calamity with his Divine-soul-sorcerer, it worked here and if it is fun for everyone, than it´s ok. In the end it is a matter of taste, for me a group of five/six is ideal.