1.12 won't be live until, what, late August/early September?
The likelihood of a hypothetical 1.13 is slim IMO, because it'd be due about the same time as TBC is rumoured to be going live.
I'd say it's more likely that 1.12 will be the pvp revamp
plus TBC-related content (questing to reopen the Dark Portal, draenei/blood elves going to the Alliance/Horde leadership and asking for help, Burning Legion starting to take a more active role, etc, etc). This is, however, pure speculation on my part.
