A common rule (that was standard in various editions), that seems to have been removed since the 5th edition playtest, is the allowance of “strength and a half” when wielding a weapon in two hands. The general idea behind this is to give each weapon style a focus: weapon + shield = more defense, weapon + weapon = more attacks/chances to hit and versatility, weapon with two hand = a powerful strike. For example we have a character who has a +2 to strength. He could wield a longsword and a handaxe having two attacks, with two chances to hit, and dealing 1d8 + 4(str) + 1d6 damage, resulting in a max damage of 18 (excluding criticals). Alternatively if he were to use a greataxe he would have a single attack dealing 1d12 + 4(str) resulting in a max damage of 16. As is using two weapons you would not only get two chances to hit but also a higher potential for damage on top of potentially having one weapon versatile and one thrown meaning you can manage any form of combat. With the strength and a half rule in place he would have an extra +2 to attack and damage (strength times 1.5 = 4(str) x 1.5 = 6). This would at least increase his max damage output max to match at 18. From here the two styles would further become differentiated by various feats and class abilities.
When wielding a weapon in two hands you may add your strength at 1.5 times the normal rate to both attack and damage rolls. This excludes any weapons without either the “two-handed” or “versatile” properties.