This whole business of the Bren being 'too accurate' is a bit bizarre, especially when tied to a claim of the beaten zone being "too small."
The beaten zone of any automatic weapon is very, very long and very, very narrow. For modern GPMGs, while the size will depend on any number of factors, a typical beaten zone (the eliptical shape into which the bullets will fall on the ground) is but metres wide and hundreds of metres long. Essentially, on a 1:50,000 map, it's like a pencil line 1/2" long.
No machine gun is properly used by swinging it back and forth, spraying bullets like a garden hose watering the vegetables.
In the defensive, one sites one's machine guns so as to place the beaten zones across likely enemy axes of advance. So long as the guns keep firing, nobody and nothing can cross that area unless it's armour-plated. That it's even one metre wide is immaterial - the opposition can no more run between bullets without getting hit than they can through raindrops without getting wet.
It's not much different in the offence. Sure, you can wave it back and forth in the hopes of keeping the opposition's heads down, but you could do that with a laser, too. Having a very wide beaten zone would not only broaden the slice of ground the bullets are landing in, but would also result in many more of your bullets coming nowhere near the opposition, going either overhead or burying themselves in the ground in front.
If the cone of fire (that cornucopia-like shape down which the bullets fly in mid-air) gets wide enough to please such commentators, the weapon will be too inaccurate to be able to reliably engage targets at a distance.
Saying a weapon is too accurate is like saying a woman can be too pretty or a beer too tasty.