(my limited understanding is that Ubuntu wants packages to be in Debian first)
Ubuntu will accept a package that is not in Debian. There is a team that can then help you get your package into Debian, if you wish.
wxFormBuilder has the same dependency on wx2.8, but has been accepted into Ubuntu Hardy.
However, Hardy is now in feature freeze, so Code::Blocks would need to get a feature freeze exception, or wait for the next one.