Okay, so this is my current thought for the skill tree. Instead of assigning points, you'll just have a level, and we'll level up frequently(if you go missing you may miss level ups, so you'd be weaker than the rest when you returned). And the different skills will have different level requirements depending on your element percentages. 

Example(using the 30 points total): 

Monk skills, Glide. 
Level requirements:
1(25-30 Air)
2(20-24 A)
3(15-19 A)
4(10-14 A)
5(5-9 A)
6(<5 A)

That way you won't have to sacrifice skills, and instead you'll learn them in the logical progression for your class and element ratio. 

I truly don't think that that is too complicated, does anyone disagree?