For an eSoS:
Misses still miss.
2 - 14 compare 1.5 * x to 3 * x, or an overall loss of 1.5 * 13 * x = 19.5 * x
15 - 18 compare 1.5 * 3 * x to 3 * x, or an overall gain of 1.5 * 4 * x = 6 * x
19 - 20 compare 1.5 * 6 * x to 6 * x, or an overall gain of 3 * 2 * x = 6 * x
Net loss of 19.5 - 12 = 7.5 * x over the average 20 swings.
Glancing blows go from 19 * .75 * .6 * x = 8.55 * x to 1.5 * 8.55 * x, or a gain of 4.275 * x. The increase in Vicious damage cannot be directly compared in the same way, but in raw terms it will be an increase of .5 * 19 * 21 = 199.5 damage over 20 swings. If the barbarian's base damage is less than 199.5 / 3.225 = 61.8, they will do more damage in helpless than they did in autocrit, but a barbarian's base damage with an eSoS is almost certainly higher than 61.8.
Now, for a falchion, you would only have lost .5 * 13 * x and gained 1 * 4 * x + 2.5 * 2 * x, or a net gain of 9 - 6.5 = 2.5 * x over 20 swings from main blows alone. Of course, you probably shouldn't have been using a falchion in auto-crit anyway, but it is an interesting result.