Just a side note, to encourage the use of spears in a Greek campaign. In the past, I have allowed anybody with a 2-handed spear or polearm to use their reaction to attack somebody that comes in range, like Polearm Mastery. If they do so, they give up their action next turn. It means that charging into a wall of spearmen can be scary, you might not live to get your attack off. If you do, they are in trouble next turn. A rule like that, combined with a Fighting Style and Feat built around spears could see them become used more.
To encourage the use of the gladius, clubs and spears, one could opt for the common houserule of not much caring what weapon somebody is using. Simple skilled people do d6, Martial do d8, or Two-handed do d10/2d6. Adjusting for properties of course. A spear in the hands of a warrior should be as good as a longsword, d8 versatile. The same spear in the hands of a simple weapon using chump is just d6.
To encourage the use of the gladius, clubs and spears, one could opt for the common houserule of not much caring what weapon somebody is using. Simple skilled people do d6, Martial do d8, or Two-handed do d10/2d6. Adjusting for properties of course. A spear in the hands of a warrior should be as good as a longsword, d8 versatile. The same spear in the hands of a simple weapon using chump is just d6.