Which army were you in? 
The SAW that I know is very light. Only the balance is not so good
cos the back very light and the front is heavier. If you find it
heavy you must be really weak. It weighs about the same as the
M16/M203 package.
Even the small guys in my reservist platoon had no problem with the
SAW.
The SAW primary role is to give the section its own effective
automatic fire during the assault - that's why it is called Section
Assault Weapon.
I can provide flank security with a SAW, or a rifle or M203. But I
cannot use the rifle or the M203 to provide automatic fire during
the assault.
To brush the cobwebs from your brain, the SAW can only fire in
automatic mode, there's no switch for burst fire.
And contrary to what you said, our SAW can hit everything that you
can aim at even if you squeeze the trigger and don't let go until
your magazine is empty.
Esepcially in the shorter range context of an ambush.
Don't believe me? Go check out the Ultimax video on Youtube. The
guy squeezed off 1 whole C-mag drum while standing up and never
released the trigger. And he was writing "S" shapes in the water
with the bullets.
Can't hit anything?
Question is, "U" ever been to army?