The Power Modifier Concept

[Sandpark]

The whole point is to not have prioritization in it's use. It adds a level of performance choice rather than just stat number solely. I don't consider it annoying, it's a guaranteed critical hit for users with an accuracy vs power risk reward. When you play any good sports videogame, the actual tactile pressing of keys determines the accuracy of the shot. One point I want to make is this is not a charge system, a charge system has a guaranteed power advantage by holding it down longer. Just as a guitarist can choose to hold a note longer or lightly and briskly play notes for speed alterations, so to this concept works.

A tier selector like you mentioned would work too, however that wouldn't change the dynamics of how a skill is cast only that you cast different skills, basically a charge button.

It is based off momentum.
If I swing a bat fast or tap a light swing I might be more accurate hitting a fast ball but it would not travel as far.
If I use a bit more strength, it would be a little less accurate but travel further.
If I use all my strength, I would be way less accurate but when I hit the ball it will travel max possible distance.

Now the meta is cast your heart out but you don't really have any control over how your skills are cast minus stats and gear, you cast the same way as X other <insertclasshere>. This adds a dynamic with momentum where as in you might all draw from the same skill pools, but the cast style is determined by the user.