The Concept Ablity System.
Here is my suggestion for an ability system, with this system.
One chooses from a set of simple "Concepts" with a one to five point level
scale. If you wanted a skill to use a gun, you wouldn't choose a "Gun" skill.
You'd choose a "Damage" and a "Distance Modifier" concept. I'll explain soon.
Let me give you an example of concepts:
"Lift" This concept skill allows you to lift heavy loads
"Move" This concept skill allows you to move heavy loads
"Damage" This concept allows you to cause damage
"Throw" This concept skill allows you to throw objects a great distance
Now let's say you wanted an ability like "Telekenisis" you wouldn't choose a
pre-made ability like that. You'd choose the concept skills "Lift" "Move" "Damage" "Throw"
and COMBINE THEM. Then name the ability what you see fit.
Now let's see what we have.
TELEKENISIS (distance modifier):
Lift: LV.1
Move: LV.1
Damage: LV.1
Throw: LV.1
This new ability that you have customised has four areas you can level up.
Lift will determine how much you can lift with this ability.
Move will determine from how far you can pick up things.
Damage will determine how much damage you cause with this ability.
Throw will determine how far you can throw with this ability.
You notice the (distance modifier) I put in that ability title? If that modifier wasn't there then
that ability would do the same thing, only you would have to get close to your target to do it.
Adding a distance modifier would probably have some penalty.
If someone does not have a lift ability at level 1 or higher, they can lift heavy loads any human
can. If someone has a lift ability at level 1 they can lift more than the average human.
A lift at level 5 would allow one to lift hercules-like loads.
With this system you can not only create custom abilities without much assistance from
a GM. But you can also customise the abilities by focusing levels in one area or another.