in live chats pay girls to make members reccur, don't make members pay more for one on one - it should be included, like whichever member girl enjoys most, she could go with one on one with him/her - this will add more life on video chats. main point to innovation is interactivity and involvment.. once you keep your members happy and busy w/o extra cost for them you set.
i'm not sure how current numbers add up in scheme of paying girls, i guess they currently earn commisions from 1on1 plus low hourly, escaping such pattern might be expensive but thinking of the long-run could play a trick.
once that's done, next step is tight integration of such services with personals services (+atracting female members), giving members place to meet online and take it offline
by this time i expect video conferencing to be advanced enough and as fun as IRC used to be back in the days.