4 is perfect for a D&D party. One fighter class, one healer/buffer, one offensive caster and one utility character. And with multiclassing you can mix and match to really make the 4 suit your playstyle. In this case more does not equal better.
All of this is wrong.
Multiclassing is also not the answer because of the level 10 cap. You need 3 levels in a class to get the basic archtype unlocked, and that means you will be missing out on the second ability score increase or feat. Less than three levels and the class doesn't offer much. If you go more than 3 levels, it weakens the primary class further.
