Someone already did the research. I found it in a post somewhere on the forums a while ago and copied it to my notes:
Relative enhancement values
Cost/level
Accuracy,102.4
Damage,100
Healing,100
Endurance Reduction,93
Recharge Reduction,93
Cone Range Increase,88.27
Range Increase,80
Recovery Increase,80
Taunt,76
Slow,73
Disorient Duration,73
Accuracy Debuff,73
Defefense Debuff,73
Immobilzation Duration,73
Defense Buff,70
Hold Duration,66
Resist Damage,66
Run Speed,66
Sleep Duration,66
Flight Speed,63
Activation Acceleration,60
Confusion Duration,56
To-Hit Buff,50
Fear Duration,46
Jumping,40
Intangibility,35
Knockback,33
Endurance Drain,23
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-billy-
