The Fallout 76 panel, as expected, was led by director Todd Howard.
As soon as Bethesda announced that Fallout 76 would feature PvE and PvP elements, players had concerns about griefing.
But unlike past games, each perk card will have an associated point cost, and will be linked to one S.P.E.C.I.A.L. stat.
Perk Cards are the new way to build out and specialize your character: they have their own SPECIAL requirements, but as long as you meet them, you can add that card to your collection - no random rolls whatsoever (though there are also randomized Perk Packs you get every few levels). And presumably if the aggressor is of a high level, that small damage could be enough to kill any low level player quickly, thereby hurting their experience. "The "Happy Go Lucky" card, for example, increases your Luck stat by two when you're drunk, "Gladiator" boosts your one-handed weapon damage by 10%, and 'Scrounger" gives you a 50/50 chance of finding extra ammo in containers. You can also power up cards by combining them, though that will increase their point cost too. Perk Packs do seem like prime loot-box-style microtransaction territory, but Bethesda didn't say anything about plans to sell them. If you're killed, you can seek revenge and get a double reward for taking the rival down.
This suggests that mutations will be a replacement for the traits system seen in Fallout 3 and New Vegas - strange, and sometimes comedic modifiers that come with as many drawbacks as benefits. So don't worry about spending three hours in character creation then having to toss the whole thing out when your Vault Dweller looks like a weirdo in the actual game.
Past Fallout games locked you into your perk choices, but Fallout 76 will let you re-tool your character when you want. Bethesda mostly left the details of mutations for another day, but they sound like weird fun.