I personally see stealth being permanent as something that can easily be balanced. People keep saying on here, "the timer gives more strategy." Although with how slow you move you usually can't get close to them without them either seeing you as you go into stealth, or by the time you get to them you're out of stealth before you even get your attack off. Now if they did want to go the route of a timer on stealth, then the run speed should be just like normal speed. That way, you can get to the target within that time span. Or they can lengthen the timer to something reasonable enough to actually reach a target without the player seeing you go into stealth. Yes there's sprint and other abilities to help out with that, but the cool-downs usually are very long and if you were to finish off someone, you then have to wait another (X amount of minutes) to actually have stealth be useful again.