Mate, Rouges dont become 'broken' when they get sneak attack damage. They're just useless in combat without it, and their combat effectiveness is based around the assumption that they get it on nearly every single attack.And that means we should make it even easier? No.
Baseline Fighter 11, greatsword - 3 attacks, 6d6+15 damage (re-roll 1's amd 2's) so around 45 damage - and likely considerably more via GWM, Sup dice, Expanded critical or whatever from archetype and Action surge or magica weapon effects triggering 3 times.
Baseline Rogue 11, shortsword - 1 attack, 7d6+5 damage, so around 40 damage. Unable to increase much higher with feats and archetypes.
Without SA, the 11th level Rogue deals around 9 damage with his single attack, which is clearly trash.