This is a two part suggestion, but I think karma should be account bound, because I just don’t see any reason it wouldn’t be. It just makes sense that people who want to play multiple characters should still be able to amass karma for a legendary or whatever without worrying about playing the right character.
Second, I think karma should be rewarded for doing explorable mode dungeons. Even if it was only like completing one dynamic event worth from each boss it would at least add up.
Right now just chaining DEs or participating in WvW are the best ways to get karma, and while WvW is very fun, I don’t find just chaining DEs for hours to be very fun, where I do enjoy dungeons, so I think it would just be a nice little addition to dungeons.