The guidance we received from Oracle is 11.2 is the final OWB release. Patchsets will be provided thru the 11.2 database premier support period and OWB 11.2 will remain certified/supported thru the database 12c release. OWB basic functionality will still be included in 12c license as best I understand (it was not clear if patchsets would continue after 11.2 premier support ends in Jan 2015). The statement of direction has been for migration of OWB and ODI functionality into a merged product line.
My guess would be Oracle is prepping DB 12c and next ODI for release later this year and will include some kind of built-in basic ETL along the lines of OWB 11.2 in the DB and the ODI release would include some migration or interoperability to bridge the OWB/ODI repositories. I have not heard anything on this, just surmising from past history of when DB releases are announced and related functionality.
I'm a little late to respond, but wanted to share this presentation from Oracle in case you have not yet seen it.