I really like Dazzler. As for Black canary, she isn't a singer. Being a singer doesn't fit any version of Black Canary, from golden age to 2011. Like I said, making her a singer makes as much sense as making Batman a rapper, or Soloman Grundy an evil break dancing zombie. They could technically do it, but it doesn't make sense for the character.
Since she's never claimed to be one or shown to be one in any comic I've seen with her? Sure, she has the generic combat skills of every powerless vigilante, but pre-reboot she was able to match Lady Shiva, who was basically the best martial artist in the world. Now, the character is all about singing, and before that she was all about her dead husband, and before that she was just filler on that terrible New 52 Birds of Prey team.
No. PG got screwed over because all of her early New 52 appearances gave her really one personality: She liked to party and had lots of sex. She really got nothing more until maybe 4-5 issues into World's Finest. She eventually got a bit of personality in the Earth 2, but its very bland. Nothing like the pre-reboot version. Not as bad as Sex-goldfish Starfire, but still another horrible change to a female hero by DC's New 52.