Make Ancient Coin give an Upgrade, not an extra Skill Point
if Ancient Coins quest is completed, give the player the possibility to add an passive effect to one of the basic skills: As Example:
Ancient Payoff: ON ALLY CAST: Ally gets 7+1% per level slow/cc reduction when running towards you ON ENEMY CAST: Enemy deals 2+1 per level % less damage to anyone except you
Effect lasts till the skill reaches of 50% its cooldown if single target and lasts till 83% of its cooldown if multiple targets are hit.
effect strength is halved if both effects apply at once.
to make it more interesting: give the player coin stacks when collecting Ancient Coins like Gangplanks Silver Serpents. Triggering the passive costs Ancient Coin stacks.