Thanks for the input Rits , now I also researched MMORPG skill trees to see how thy work in my game, and thy don't.
You are right thy focused on a fair game play for the players(and never really getting it 100% right),when you think about it, it's clear why thy do it.
In my game however I want to brake away from the "you need to take this skill or the enemies in the new area,will crush you!" thing,so the skills are powerful e.g. a defence spell will half all damage and a power up spell will double damage of the target.
warriors will do almost double the amount of damage of a normal class and berserkers tree times as much, but both these classes will be extremely weak to magic.(Just think of the power if you double it!)
I want players to achieve balance by using deferent classed party members instead of balancing each member on it's own, this is working great so far, players who like strength have made teams of Warrior *2,Defender,Archer *2 and a support class(Healer or Alchemist) where magic users have used one wizard of each element (Fire,Water,Earth,Wind,Light,Dark), unfortunately no one used a stealth team yet.(We have Thieves,Assassins and Illusionist).
This is all data based on the old skill tree(That only two out of 9 players could use, and I was one of them!).