First there have only only level 5 level(aika money) lion heart. So you cant spent more points on it cuz of level cap. You just can spend 4 extra points compared to having it level 1, and another 4 extra points for having to put berserker to level 5 instead of 1.
The lion heart thing mostly comes from our point of view. warrior is not like solo-character the one who kills, it is mostly party character. So in our opinoin maxing out party buffs and stuns are far more important than maxing out damage.
Second is armor break. Even if no one uses armor break in Aika, doesn't there cannot be any discuss about if the skill actually works, or is it broken? Or is the armor-levels in the game really that insignificant, where 500 extra armor means nothing. Wether you have 1500 armor or 1000 armor, there should be huge difference, but when using armorbreaker, there have not much difference.
In most situations berserker doesn't seem to stack with haste, or bless, the whole buff is semi-useless. So total 8 extra points spent for 130 extra skill damage and 4% crit. Such as you are having level 1 dragon slash with 5 lion heart does less damage than having level 3 dragon slash with level 1 lion heart.