Still he is right that dual wielding is actually broken but for totally different reasons:
1. Ability modifier is NOT added to attack rolls with offhand weapon (even when the modifier is negative resulting you have higher chance to hit with offhand then your mainhand)
2. Ability modifier is added to damage rolls with offhand weapon for all classses from 1st level. This should be case only for fighter or ranger with Two weapon fightning style.
3. You can attack with two-handed weapon, change equiped weapons to two light weapons and attack with bonus action. After that you can switch to shield and pass the turn.
All of those are correct, though I suspect 1 & 2 are the result of a technical issue since the tooltips reference the rules properly; probably whatever calculation they have in there has the values switched. As for the third one, I think this is also a technical issue, although a more complicated one. I expect all of these will be fixed in time.
