Okay so i been playing guitar since 03' -ish

And i dont really know how to sweep pick all that well.

who cares right?...
I suppose it isn't essential, but it's a pretty cool technique when applicable.

That said, very few techniques are actually essential - all are good to learn, though... Of course, there will always be that one - maybe two - thing(s) that gives you all kinds of hell.
Closed. Sorry this is a music theory forum, this has nothing to do with music theory.
And no, Guitar Hero will not help. Even on expert. Really.