Changing the attack speeds and animations will negatively impact higher latency users by latency binding the output the class could do. This is similar to how Wardens currently work. Adding Revel in Victory to be triggered on Crits will across the board make the class more playable for everyone.
If we want Brawler DPS to feel more balanced we should be looking at tweaks and not wholesale changes on timings. Changing animation timings adds a whole other set of balance pass issues while passive mettle generation works within the framework of what already exists. I would want to see the Dev magnitude from the trait line changed to Crit so it is more in line with every other melee DPS, but that's a personal ask.
The majority seem to agree that adding some kind of passive Mettle Generation would make the class more enjoyable to play. The similarity to how Champs or Hunters respective point building shouldn't be the break point, Brawlers will still fundamentally play differently.
Wrecks 50 Beorning | Treebeard
"Remembering that you are going to die is the best way I know to avoid the trap of thinking you have something to lose. You are already naked. There is no reason not to follow your heart. ... Stay hungry. Stay foolish." - Steve Jobs, RIP-