Crowley's got the Angel tablet, but that doesn't mean Naomi is going to stop searching for it---or stop trying to control Castiel. Her motives will become much clearer in the last two episodes of the season, according to spoilers from Zap2It:
"You're definitely going to see much more of Naomi," executive producer Jeremy Carver says. "I think what we have now is a slightly incomplete picture of who this angel is and what she wants. I think that is something that will continue to be refined."
Would you like to see Naomi stick around for Supernatural's Season 9?