Like everyone else on every forum page you seem to misread the topic, I know I have to wait three hundred seconds for STORM to regenerate BUT I also have to wait three hundred seconds to be able to use any other shout when I have used Storm, I should just have to wait the amount of time that particular shout takes to regenerate; the bug is as follow: I use a shout which has say a thirty second regenrate period, I then switch to a shout which has a five second regenerate period and still have to wait thirty seconds.
Edit: if this is not a bug it is pretty stupid, I should be able to use Unrelenting Force thirty seconds after I have used Storm as Unrelenting Force has a thirty second downtime period.
Everyone seems to have answered you, think of it like this
there are like 20 different shouts, If each one had a separate cool down, I could use storm, the force, then fire, then ice, then summon etc etc
why even bother using a weapon or spells then?