i was talking about the duration of the skill buffs.. the buffs is ok but the duration is the problem
As was stated above; the reason for the "short duration" skills is to allow a class to be more powerful for a short period of time, while not making the class more powerful on the broad scale of time. Let me give an example;
Consider Long term buffs (buffs that last 10-15 minutes) like the Mushroom or Fire-Mario mode in Super Mario. These are buffs that stick with you for a long period of time, that give you a slight edge, but are not overpowered in the long term in relation to game balance. The mushroom just gets you more survivability for 1 more hit, and the Fire-Mario just lets you hit targets from a distance. Hardly game-breaking.
Now consider Short term buffs (buffs that last 10, 15 or 30 seconds) like the Invincibility (Star) mode on Super Mario. It would be quite unbalanced if you could run through an entire level in Mario with Invincibility on. The same concept is with EE. The short term buffs are designed to give you a significant edge on an opponent, but only for a short time.
I think the issue you are more directing to is not the duration of the buffs, but the lack of NUMBER of buffs with short duration at lower levels. But this will adjust as you progress and level up and earn more skills.