Some other games have an optional toggle to enable 'quick casting' - it would be nice to see this in Tera.
For example on lock-on heals (priest/mystic) what this could do is make the selection whilst your holding the button down and casting it on release. This get rids of additional button presses and speeds up the process.
As it is now:
¹press button > ²release button > ³hover over people > ⁴press button > ⁵release button
Quik cast enabled:
¹press button > ²hover over people people > ³release button
For some other skills it could work even faster, take the gunner skill "bombardment". At the moment I need to:
¹press button > ²release button > ³move the indicator to the desired location > ⁴press button > ⁵release button
As a somewhat seasoned caster of this particular skill I have no desire to do the whole positioning bit, I know where my crosshair is aiming and thus where the skill will be, quick cast could reduce this to a ¹² process rather than ¹²³⁴⁵. Do note the positioning could still be part of it (¹³²) but if you were to simply tap the button for it you basically perform a ¹² combo instantly casting it.
Do note I'm just giving examples of the skills, there will be many more in the game that could benefit from this.