I'll be honest here, the change to swipe not only was a huge nerf but it also was pretty kitten seems like it had little to no effort or thought put into it.*
Deadeye's mark steals a part of the enemy's soul (or something like that) and that in turn changes not only the steal skill but also the stolen skills themselves. With this in mind, I think that daredevil as a brawler should have the stolen skills change so they represent that they're skilled fighters, willing to steal and adapt the enemy combat techniques, rather than just being a common thief focused on stealing shinies. Also in order to stay in melee these stolen skills should help with defense/sustain in some way as well.
As for stolen skill ideas, I'll throw some random ones here: warrior gives you a 2s block, necro gives you a lifesteal attack, mesmer gives you a "shatter" small aoe blind, ranger gives you a trap with immob, thief gives you a fancy leap with evade frames, etc.
It shouldn't be that hard. And if it is, then the change could've waited until another balance update so we get a proper tradeoff instead of just a worse steal that happens to be unblockable (which isn't that good of a bonus anyways).