The feline origin from origins mod isn't supposed to be able to mine stone that is adjacent to 3 or more other stones without the strength effect. But if the Feline can use a hammer to bypass this and mine any stone no matter the condition, making the downside useless. Maybe make it so that if someone is a Feline then they just can't use a hammer unless they have the strength effect, since even if it did act like it should then the hammer might mine extra stone from the 3x3 area which also makes the downside less effective.