@Tzeentchian
I don't deny that an asari or krogan can be a force of nature when it comes to biotics. Even humans like Jack or biotic Shep. But I don't think the lore and gameplay match 100%. I mean Shepard with the right gear and max CD bonus can spam Pull every 2 seconds and Slam every 1.2 seconds. That's just...no.
The entire idea of "cool-down" is a very game-y one.
If the "power" is not dependent on an separate power source like Mana, it should be the same as lifting weights,
swinging a sword, or being in constant fighting.
Whichever the activity is, using biotics for example, would be dependent on the level of fatigue the character feels.
The idea that you need to "nerf" "cool-powers" like magic or biotics using artificial restrictions like cool down, just so other classes would seem balanced and worth playing, is ludicrous if you consider it only from logic and lore standpoints.
The real world is never fair or "balanced", why should another universe be different?
Humans are generally squishy and weak relatively. Top human physical potential is still very low on the food-chain when compared to animals in nature.
A trans-human of any sort will have a major advantage over vanilla human, because their potential is on an entirely different scale.
A biotic can be at a good physical condition, have more or less similar training to other special-ops operatives, AND fling around dark energy.
Physical training has diminishing returns the higher you go with it, which means that the fact that the biotic may need an hour or three a day for biotic training, will not make a big difference between him and the next soldier, hell, constant biotic training may even improve endurance compared to other soldiers.
In short, a trained biotic operative should only be limited by his own skill, his level of fatigue, and perhaps a measure of concentration when it comes to delicate uses. Which in turn would enable a more or less continuous use until physical or mental exhaustion - which is actually what is needed to fight without weapons.
A good example would be S Julia's example above: biotics in ME2 holding the bubble until near exhaustion.