How would extra attack features work?

— Hany Diab (@Debased35) July 3, 2018

Each extra attack = two more TWF attacks, at least that's my first pass. https://t.co/qOcW8il0Vf

— Mike Mearls (@mikemearls) July 3, 2018

I like the idea of freeing up the bonus action by pairing off hand attacks with each attack made as part of the attack action. I am not sure halving the damage is necessary(you and @JeremyECrawford can crunch numbers)…..

— Daniel Lieberman (@DMCLieberman) July 3, 2018

I’m not going to crunch numbers on a house rule. 😉

— Jeremy Crawford (@JeremyECrawford) July 4, 2018

Two weapon fighting as a bonus action has always bugged me. Here’s a house rule I might use: If you take an attack action, you can strike with two weapons you hold in place of each attack, but they deal 1/2 damage. You can do this with 1-handed melee and/or ranged weapons. Twitch, tell me why this doesn't work other than halving damage being a bit of a pain. I am either dumb for missing something or dumb for not just doing this like 5 years ago.

— Mike Mearls (@mikemearls) July 3, 2018

We didn't do it because we experimented with a higher number of attacks, and they significantly slowed down play in our internal stress tests.

— Jeremy Crawford (@JeremyECrawford) July 4, 2018

You’re thinking of the reaction fighter. We never questioned the handling time of core functionality – that path rewrites casters. TWF was a spreadsheet problem.

— Mike Mearls (@mikemearls) July 4, 2018

I’m thinking of the many stress tests the rest of the team and I did on higher numbers of attacks for various weapon-focused classes. I’m not thinking of the reaction fighter.

— Jeremy Crawford (@JeremyECrawford) July 5, 2018