WhileLori Greiner will surely be sad to see Shark Tank costar Mark Cuban eventually leave the series, she already knows who she wants his replacement to be! Greiner spoke about a future cast shake-up while attending The Hollywood Reporter’s Women in Entertainment Gala on Thursday, December 7. “I’ve wanted Oprah for years!” she declared. “So what can I say? Let’s manifest that! Yes, world, manifest that!” However, the blonde beauty, 53, pointed out that Cuban said he doesn’t plan to leave until after Season 16, and they’re currently in the fifteenth season. “We still have season 16, and that wo…