Autoattack timer

[speedycerv]

Posted this on my beta thread but I'll post it here too:
My question is this, why can't this be done:

Just as spell casting looks at the spell's casting time/recovery time, in order to generate the bar, why can auto attack not be done the same way?

The bar doesn't change mid way when your casting speed changes, so why can't there be a bar made that reads the delay from the weapon, [which is dynamic data isn't it (I mean it is in my top bar of profit reborn)] and use the delay the same way you use the cast time of a spell read from the spell? I'm guessing this is how it would be done.