I've done a lot of dual-wielding in BG3 during my eight plus play throughs of early access, and I'd disagree that it's bad. It is by design not equally accessible to all, and hence I can see the frustration for those who might want to play a dual-wielding barbarian, but as another said, that isn't the way 5e is designed. It is viable on a fighter and incredibly good on a Ranger, which is the iconic dual-wielding class. I've played both Str and Dex build rangers and have found that dual-wielding is very good if built correctly. In fact, I'd say it's some of the highest DPS I've seen. Yes, there are times where you'll want to drink a potion instead of taking that extra attack, but most of the time you'll be able to kill things more quickly thus negating the need for potions. Similarly, there will be occasional situations where you can shove someone to their death instead, but in that case you'll hardly begrudge the lost attack. More often than not, however, you'll get one extra attack per round, and that is great.
This works the best with the ranger, because Hunter's Mark and Colossus slayer will add extra damage to those attacks, which has often allowed me to kill bosses in a single round. In prior playthroughs I would often cheese Gekh Coal by pushing him off a ledge. Larian removed this option in patch 9, but it hardly mattered. My dual-wield ranger killed him before he could get off a single action.
Yes, there are other options for that bonus action, and knowing when to forego the extra attack to do something else and when to not just adds to good strategic gameplay decisions in my IMHO. But the fact that it doesn't apply every round doesn't make it not good most of the time, which it is.
Some have critiqued that dual-wielding requires a feat and a combat style. I think the latter is required but not necessarily the former, which sometimes is a good call and sometimes isn't. Unless one is playing a thief rogue who is making two offhand attacks it probably isn't worth it if we can't apply the extra damage from our primary ability. The feat, however, is optional, and better on a strength build that a dex build. With a strength build it provides us vastly superior weapon selection in addition to the AC bonus and is worthwhile, but on a dex build it only gives us access to rapiers, and in that case as far as early access is concerned we might as well just take extra dexterity which effectively gives us the same damage upgrade while also giving us better accuracy and all the other benefits of dexterity. We'll still do a lot of damage, especially with help from Hunter's Mark and Colossus Slayer.
It is also worth noting that at least for Str-based rangers access to a wide variety of weapon actions is better than I thought it would be. In my earlier playthroughs I kind of ignored weapon actions, but some of them are very good. My Str-based ranger wielding Faithbreaker and Phalar Aluve had access to concussive smash, backbreaker, lacerate, and pommel strike all at the same time, which gave her lots of options for making opponents more vulnerable to attacks or making them take extra damage within a single encounter.
As far as DPS goes, it is also important to keep in mind that more attacks means more opportunities to hit. Even a well-built character will miss with their weapon attack sometimes, and it's always satisfying when my first attack misses but the offhand hits. If I weren't dual-wielding I'd have dealt no damage with the attack but because of TWF I was able to still do some.
I don't think TWF is by any means broken, and it certainly does require or encourage certain class choices and careful building and playing. As a TWF love I certainly wouldn't complain at all if Larian improved it, but I don't think its inherently bad.
