I think warrior's Charge skill is quite useless and peole are regretting the points spent after they leave Tier1.
It give additional damage (in the 1st attack only) with the maximum of 20 damage. It matters only in the 1st Tier. Above, this 1 time 20 damage bonus becomes ridiculously small, negligible value.
So, I suggest to make it in percentage of the damage dealt and use multiplier similar to critical hits. So the 1st hit will be 1.5x, 2x, 3x, 4x, 5x or so.. stronger than normal hit. Values need to be played around to get the feeling which are right