If I may swap out +1 shortbow, for +1 rapier which allows the application of booming blade:
Advantage
W/o = 25.85
W/adv = 35.583
W/elvish = 39.65 *as we get to latter, this is actually higher than the non-crit average, crits are starting to actually matter statistically
The straight average is only 37 to the barbs 44 so you may be right that the barbarian will feel pretty good about hitting twice, but my quick math is that will only be about a third of the time, even with advantage
More to my earlier point though,
For the rogue with the shortbow, let's just add extra attack like is sometimes recommended
so we have 1d6 + 5, 1d6 + 5 and 4d6 sneak attack dice,
advantage:
W/o 23.67
W/ 31.19*
I dropped it being a +1 weapon for this math, and as it turns out, we are beating those barbarian with GWM numbers in both categories, no feats or special options, just extra attack and sneak attack with a shortbow. This is what I mean when I say that adding extra attack may be too much, It makes featless no multiclass rogue beat out optimized builds, potentially opens up those optimized builds for rogue on top of that, and has a number of other potential knock on effects with things rogue is already capable of.
*this may be a little high, when calculating for crit sneak attack is frustrating as hell since technically the first hit not critting reduces the chances of the next hit critting with sneak attack, so it is not quite the same as advantage numbers, so this may be slightly high by a point
Edit @Dork_Forge for some Yes, and
For the Two-weapon fighting example, you don't even need the fighting style for a chunk of that, the bonus action attack is a bit lackluster on its own, but a lot of the benefit is for sneak attack with increased consistency.