We've already gotten plenty of shows/games/movies/novels with Robin, Joker, Two-Face, Penguin, Riddler, Batgirl, ect. I think it's about time we let some new characters get some time in the spotlight.
Right. I think people forget (heck, even I forgot until now) that Batman:TAS
was itself the screen debut of a number of notable characters from Batman comics: Harvey Bullock, Lucius Fox, Leslie Thompkins, Zatanna, Poison Ivy, Ra's al Ghul, Talia, Killer Croc, Bane, Man-Bat, Hugo Strange, Maxie Zeus, the Ventriloquist, Rupert Thorne, Tony Zucco, Professor Milo, and even Two-Face (though Harvey Dent had appeared in the '89 Burton movie). It was also the first screen appearance of Arkham Asylum, though the institution had been name-dropped in an episode of The Flash
. Not to mention that it created several characters who'd later be added to the comics, such as Harley Quinn, Renee Montoya, and Lock-Up, plus various original characters all its own like Summer Gleeson, Veronica Vreeland, HARDAC, Roland Daggett, Kyodai Ken, Baby Doll, etc. So if B:TAS, everyone's most admired Batman series, could achieve success by featuring so many comics characters never before adapted to TV and creating so many of its own, why can't BTB do the same?
And besides, if they did do the more familiar characters, they'll probably put they're own spin on them that Kirk55555 and people like him will still hate. At least with them doing the new characters, people aren't as likely to be upset about them getting the character "wrong".