Miyamoto Musashi would disagree.As it should. An offhand dagger is just about viable if you don't want to lug a shield around with you, but fighting with two big heavy weapons is so stupid even Conan doesn't do it.

Miyamoto Musashi would disagree.As it should. An offhand dagger is just about viable if you don't want to lug a shield around with you, but fighting with two big heavy weapons is so stupid even Conan doesn't do it.
Mechanically this works well. I'm not quite sure how to wrap my head around why some characters mechanically TWF differently than others. Great mechanical solution - but totally not fiction driven - which makes it feel a bit less elegant.
What would the numbers look like if the bonus action allowed each weapon to apply the ability bonus?
Flavorwise, the bonus represents two separate thrusts, as opposed to the weapons maneuvering in concert.
Case 1: You were engaging enemies without the rest of your party and thus deserve surprise but that's not really something we want to count in the positive category...
Case 2: The creatures in question must effectively not spot anyone in the party for you to surprise them. That's a very very rare event and one that the dex dual weapon user might make happen 2 to 4 times as often as if he were replaced by a str heavy armor user - however, 4 times of a really tiny number is still a really tiny number and will have virtually no impact.
That's something else to consider, that dex fighters typically get better skills and better initiative. Maybe their damage should be a little less than a heavy armored great weapon user?
DM in my games always ignores the drawing sheathing 2 weapons. If your DM's don't and you think TWF absolutely sucks - this goes a long way toward helping it.
The ability to compentently use a bow is one of the biggest benefits of TWF over great weapon fighting. That's also a reason their damage maybe should be lower overall.
That party everyone was Dex based or trained in stealth. One or two may have had 14 Dex.
It's not hard to beat npc passive perception.
I don't think it's a problem that a great weapon deals more damage. Even then it's competitive tier two or even tier 3 if there is no fighter with a 3rd attack.
You get other benefits if Dex based. Switching to bows, stealth, skills. Without feats it's fine, it's the -5/+10 feats though that blow it out.
I let in a 3pp feat that lets you Stack str and Dex on light weapons. Extra 2-4 damage per attack helps. .
I recommend you buy that for $1 or houserules. Unless you play AL only.
I have thought about boosting the dual Wielder feat to give a small damage bonus on attacks while wielding two weapons, or perhaps adding a reaction attack when a melee attack misses you. Or both.
As for ambushing, there’s also group stealth checks. And magic heavy armors that don’t impose disadvantage on stealth, and Pass Without Trace.
We ambush people a lot, even in the campaign that has two plate armored heavies. With PWT, even a roll of 5 beats most monsters passive.
Big fan of PWT. Individuals can still get surprise rounds and I had a halfling hiding behind others so lots of surprise rounds.
I think RAW surprise only happens for a whole “side”, but I do prefer to rule differently. If nothing else, the assassin is basically garbage in a game that isn’t lenient with getting surprise.