The easy solution would be to cut the Diva roster in half and unify the Women's and Diva belts. Keep something like 8 or 9 Divas top and let the Divas work both Raw and Smackdown, depending on who has the strap. For the show that doesn't have the Women's Championship storyline, make sure to develop the next contender through a secondary storyline. It's gonna be much more easy and you can have the fans more interested in your Women's Division.
TNA might have as many Knockouts but at least, they created a secondary title so those not involved in singles can have a shot at the Tag Team straps. So, that's better in my book.